JP3118047U - Squib - Google Patents

Abstract

Provided is a squib that prevents disconnection of a capacitor and destruction of the capacitor due to variation in an interval between electrode pins.
A cup body and a plurality of electrode pins are insulated and held from each other, and an embolus that closes the opening of the cup body is provided. In the squib installed by contacting the ignition agent with the SCB chip that is connected and ignited by energization from the outside,
Among the plurality of electrode pins, two electrode pins that are electrically in parallel with the SCB chip and having high rigidity for maintaining the gap between the electrode pins on the outside of the cup body. A body base is mounted, and a capacitor electrically connected to the electrode pin pair is placed on the base.
[Selection] Figure 1

Description

  The present invention relates to a squib mounted on a gas generator or the like used in an automobile safety device such as an air bag.

Conventionally, various electric squibs have been developed as a squib for a gas generator for inflating an airbag mounted on an automobile.
The squib usually has a metal pin for electrical connection with the outside, and a heating element for igniting explosives at the other end of the metal pin.

  Previously used igniters have used a bridging wire to ignite the igniter. Nichrome wire is used as the bridging wire, and if the wire diameter of the bridging wire is too thin, it cannot be attached. In addition, since the bridging wire having a diameter that can be attached has a large heat capacity, it takes a long time for the bridging wire to reach the ignition temperature of the igniting agent after being energized. Sex is not completely obtained.

  On the other hand, the semiconductor bridge is a generic term for bridges manufactured by using semiconductor technology such as vapor deposition, but an igniter using a semiconductor bridge compared to a bridging wire uses a thin film bridge with a thickness of several microns. Therefore, the heat capacity can be reduced and high-speed response can be provided. With a bridging wire, it takes about 800 to 1000 microseconds to heat to the ignition point, but with a semiconductor bridge, the igniting agent can generally be ignited in about 100 to 200 microseconds. Thus, since the semiconductor bridge can generate heat for igniting the igniting agent in about 100 to 200 microseconds, high-speed ignition is possible.

  However, when such a semiconductor bridge having a small heat capacity is used, there is a risk that the squib may misfire due to noise such as external static electricity.

Therefore, as a measure for preventing false ignition against static electricity, a method is known in which a capacitor is installed in parallel with the semiconductor bridge and the static electricity discharged by this capacitor is absorbed (for example, Patent Document 1).
In addition, the capacitor is arranged so that it does not cause the destruction of the capacitor due to the influence of chemical components contained in the igniting agent or the pressing force of the squib that presses the igniting agent against the bridge. A method of installing a capacitor between electrode pins is also known (for example, Patent Document 2).
Japanese Patent No. 3,136,144 Japanese Patent No. 3,648,256

  However, since the technology described in Patent Document 1 described above incorporates the capacitor in the cup body that contacts the igniting agent, the capacitor deteriorates due to the influence of chemical components contained in the igniting agent, Alternatively, when a squib of a type in which an igniter is assembled by pressing contact with an electric bridge portion is produced, there is a problem that the capacitor is excessively applied and is destroyed.

  Further, the technique described in Patent Document 2 described above does not describe any specific means for attaching a capacitor between electrode pins, and simply attaching the capacitor with solder or the like causes an external pressure applied to the electrode pin during handling. It has been found that the distance between the electrode pins fluctuates due to the addition of the capacitor, which causes the capacitor to be disconnected or severely damaged.

  The present invention advantageously solves the above problem, and can effectively prevent false ignition caused by electrostatic discharge due to electromagnetic noise from the outside without causing deterioration or destruction of the capacitor. The aim is to propose a squib that can be used.

As a result of intensive research to achieve the above-mentioned purpose, the inventors have not made a capacitor directly between the electrode pins, but rather a hard, one that suppresses the variation in the distance between the electrode pins. It was found that it was extremely effective to install it through the body base.
The present invention is based on the above findings.

That is, the gist configuration of the present invention is as follows.
(1) A cup body and a plurality of electrode pins that are insulated and held from each other and have an embolus that closes the opening of the cup body. The cup body has an ignition agent and is connected to the electrode pins. In the squib that is installed in contact with the ignition agent, the SCB chip that is ignited by energization from the outside,
Among the plurality of electrode pins, two electrode pins that are electrically in parallel with the SCB chip and having high rigidity for maintaining the gap between the electrode pins on the outside of the cup body. A squib characterized by mounting a body-shaped base and installing a capacitor electrically connected to the electrode pin pair on the base.

(2) In the above (1), a squib characterized in that a part of the electrode pins and the substrate with a capacitor are covered with a resin mold.

(3) In the above (1) or (2), the equivalent series resistance of the capacitor is 100 mΩ or less.

(4) The squib according to any one of (1) to (3), wherein the capacitor is a ceramic capacitor.

(5) The squib according to any one of the above (1) to (4), wherein the capacitor has a capacitance of 0.1 to 10 μF.

(6) In any one of the above (1) to (5), the means for fixing the base to the electrode pin pair is any one of solder, conductive epoxy resin, welding, and contact by a spring. Squibb.

The effects of the present invention are enumerated as follows.
(1) In the case of a squib that assembles an igniting agent by pressing contact with the bridge in the cup body, it is possible to prevent destruction of the capacitor due to pressing force.
(2) When a capacitor is installed via a hard base, it is effective to block the capacitor connection and destroy the capacitor due to fluctuations in the distance between the electrode pins even when an external force is applied between the electrode pins. Can be prevented.

The present invention will be specifically described below.
FIG. 1 is a sectional view of a squib according to the present invention.
In the figure, reference numeral 1 denotes a cup body, 2 denotes a protective cover thereof, and the protective cover 2 can be omitted.
Reference numeral 3 denotes an igniting agent. As the igniting agent 3, one containing zirconium in its composition is suitable. In addition, those containing titanium hydride, boron, tricinate and the like are advantageously adapted.

Reference numeral 4 denotes an SCB (Semiconductor Bridge semiconductor bridge) chip as a heating element. The SCB chip 4 has a bridge structure in which a metal and an insulator are laminated, and can have a high-speed response compared to a bridging wire.
As the bridge structure, a structure in which titanium and SiO ₂ (or boron) are alternately laminated on a silicon substrate is advantageously suitable. The thickness of each layer is preferably about 0.05 to 10 μm. A more preferable film thickness is 0.1 to 4 μm.
Other bridge structures include a structure in which one or more compositions selected from a combination of nickel-chromium alloy, nickel, aluminum, magnesium and zirconium, and a combination of calcium, manganese, silicon dioxide and silicon are alternately laminated. It can also be applied. Further, the squib of the present invention is not limited to the above structure and can be effectively applied to general SCB.

Reference numeral 5 denotes an embolus, and an electrode pin 6 for electrically connecting to the outside is fixed to the embolus 5 by a glass seal 7. Thus, by fixing the electrode pin 6 with the glass sealing 7, electrical insulation can be ensured, maintaining high airtightness. The embolus 5 and the cup body 1 are integrated by means such as laser welding, so that the inside of the cup body is sealed under high airtightness.
The electrode pin 6 is connected to the SCB chip 4 inside the squib, and transmits an external current to the SCB chip 4.

  Reference numeral 8 denotes a base, 9 denotes a capacitor installed thereon, and 10 denotes a resin mold that covers the bottom of the embolus 5 and the base 8 with the capacitor 9 described above.

Hereinafter, the above-described substrate 8 and capacitor 9 will be described in detail.
2 (a) to 2 (c) show typical substrate shapes, wiring patterns, and capacitor installation states.
FIG. 2 (a) shows that a flat plate having a rectangular shape is provided with two through holes 11 into which two electrode pins are inserted, and a substrate 8-1 having a conductive path 12 extending from the through hole 11 on the flat plate. This is a case where 9 is placed. FIG. 2 (b) shows a base plate 8 in which two through holes 11 into which two electrode pins are inserted are provided on a flat plate having a circular shape, and a conduction path 12 extending from the through hole 11 is provided on the flat plate. 2 shows a case where the capacitor 9 is mounted.
FIG. 2 (c) shows a rectangular block, but a thick block with two through holes 11 into which two electrode pins are inserted, and a conduction path 12 extending from the through hole 11 is formed on the side of the block. A capacitor 9 is attached to the base 8-3.
In any case, it is preferable to coat the inner peripheral surface of the through hole 11 with a conductive material.
2 (a) to 2 (c) all illustrate the case where there are two electrode pins, but in the case where there are three or more electrode pins, the electrode pin pair to which a substrate with a capacitor should be attached. Needs to be selected in parallel with the SCB chip.

Furthermore, in any of the above-described FIGS. 2 (a) to 2 (c), it is important to use a material having high rigidity so that the distance between the electrode pins does not change even when an external pressure is applied.
As such a material, ceramic is optimal, but other insulating substrates such as a glass epoxy substrate and a plastic plate are also advantageously adapted. Usually, the base is provided with wiring for electrically connecting the electrode pin and the capacitor.

As described above, in FIGS. 1 and 2, the case of having two electrode pins has been described. However, the present invention can also be applied to a squib having three or more electrode pins. However, in this case, it is important to select two electrode pins that are electrically parallel to the SCB chip among the plurality of electrode pins.
In addition, the present invention can be applied to any type of squib as long as it has a plurality of electrode pins for electrical connection to the outside, and the internal structure of the squib is not restricted. Absent.

Furthermore, it is preferable that the base with a capacitor installed as described above is covered with a resin mold.
This is because by embedding a capacitor in a resin mold, it is possible to effectively prevent the impact, temperature, humidity, etc. applied to the capacitor, and also protect it from the force acting between the capacitor connection and the electrode pin. Because it can be done.

The equivalent series resistance, which is the resistance value of the capacitor, is preferably 100 mΩ or less.
This is because the lower the resistance value, the more effectively the static electricity can be absorbed on the capacitor side. In this regard, aluminum electrolytic capacitors and tantalum capacitors have high resistance values, so that some current flows to the SCB side and it is difficult to effectively prevent electrostatic discharge.

Furthermore, ceramic capacitors are advantageously adapted as capacitors.
This is because the ceramic capacitor has a low impedance value (equivalent series resistance) with respect to the frequency characteristics and is excellent in noise absorption characteristics compared to the above-described aluminum electrolytic capacitors and tantalum capacitors.
As such a ceramic capacitor,
1. I-type ceramic capacitor (TiO ₂ ): For temperature compensation Type II ceramic capacitor (BaTiO ₃ type, PbO type): For high dielectric constant III type ceramic capacitor (SrTiO ₃ semiconductor type): for high dielectrics, etc., all of them are suitable in the present invention, and may be properly used according to the application.
Such a ceramic capacitor is very good in terms of performance, but has a weak point that it is weak against stress in the axial direction. Therefore, when the capacitor is installed, the two pole directions of the capacitor connect the two electrode pins. It is preferable to arrange them so as to be substantially at right angles to each other.

The capacitance of the capacitor to be used is preferably about 0.1 to 10 μF.
As the capacitance of the capacitor increases, the time required for charging also increases, causing a problem in high-speed response. For example, when the capacitance of the capacitor is 0.47 μF, it is 0.94 μsec, 2 μF is 4 μsec, and 10 μF is 20 μsec.
In the present invention, the purpose of using the SCB chip as the heating element is low energy and high speed ignition, so if the capacitance of the capacitor is large, the high speed response is rather hindered. In addition, when the capacitance of the capacitor increases, the size of the capacitor also increases, making it difficult to install between the electrode pins.

  In addition, although the fixing means of the board | substrate with respect to an electrode pin is not restrict | limited in particular, the contact by solder | pewter, a conductive epoxy resin, welding, and a spring etc. fits advantageously.

1 is a cross-sectional view of a preferred squib according to the present invention. It is the figure which showed the typical board | substrate shape according to this invention, the wiring pattern, and the installation state of a capacitor | condenser.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Cup body 2 Cup body protective cover 3 Ignition agent 4 SCB chip 5 Embolization 6 Electrode pin 7 Glass sealing 8 Base 9 Capacitor
10 Resin mold
11 Through hole
12 Conduction path

Claims (6)

A cup body and an embolus that holds the plurality of electrode pins insulated from each other and closes the opening of the cup body are provided. The cup body includes an ignition agent and is connected to the electrode pins from the outside. In the squib installed with the SCB chip that ignites when energized in contact with the igniting agent,
Among the plurality of electrode pins, two electrode pins that are electrically in parallel with the SCB chip and having high rigidity for maintaining the gap between the electrode pins on the outside of the cup body. A squib characterized by mounting a body-shaped base and installing a capacitor electrically connected to the electrode pin pair on the base.   2. The squib according to claim 1, wherein a part of the electrode pins and the substrate with a capacitor are covered with a resin mold.   3. The squib according to claim 1, wherein an equivalent series resistance of the capacitor is 100 mΩ or less.   4. The squib according to claim 1, wherein the capacitor is a ceramic capacitor.   The squib according to claim 1, wherein the capacitor has a capacitance of 0.1 to 10 μF.   6. The squib according to claim 1, wherein the fixing means for the base to the electrode pin pair is any one of solder, conductive epoxy resin, welding and contact by a spring.

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