AT500478A1 - Detonator for a pyrotechnic gas generator, is formed by enclosing a detonating pill and its connection members, in an injection moulding - Google Patents

Abstract

A process for producing a detonator for a pyrotechnic gas generator, especially for airbags or seat belt tensioners, comprises forming a detonating pill (1) with connection members (3). The pill is enclosed in an injection moulding, along with the connection member pill connection points.

Description

• · · 4 • · · ··········

The invention relates to a method for producing a detonator for a pyrotechnic gas generator, in particular for airbags or belt tensioners, which has a firing head with terminal lugs. It further relates to an igniter for a pyrotechnic gas generator, in particular for airbags or belt tensioners, which has a firing head with terminal lugs.

Such detonators are incorporated in gas generators used in vehicles to activate safety devices in the event of an accident. Such detonators are exposed to a variety of adverse environmental conditions, such as shock, shock, moisture, dust and high temperatures in the vehicle.

Such igniters are usually installed in a propellant charge housing, wherein the sealing of the housing usually takes place by means of an O-ring. However, moisture can sometimes penetrate into the housing despite the O-ring. If moisture penetrates to the ignition head, it slowly becomes useless.

Furthermore, so-called GTMS igniters (GTMS = glass to metal seal) are known. These igniters, which are used for very high-quality gas generators, have to dispense the contact pins from the inside of the housing via a glass-metal passage which hermetically seals the igniter or the gas generator. As a result, while a secure protection against the ingress of moisture is given, but this advantage comes at a high manufacturing cost.

The aim of the invention is to avoid this disadvantage and to produce an igniter of the type mentioned, which is characterized by a high level of security against the ingress of moisture and can be hersteilen with little effort. · * T t # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # #. * · • · · · · · ·

The manufacturing method according to the invention is characterized in that the firing head is completely inserted and the injection lugs are injection-molded into the connection lugs, at least with the regions immediately adjacent thereto.

Such a wrapper can be made very easily and with little effort. This is especially true for large quantities. Nevertheless, it is ensured that no moisture can penetrate to the ignition head.

Since the material detonates very easily in the ignition head, it was not clear from the outset whether it would cope with the stresses of injection molding. Surprisingly, this is the case. It should be noted, of course, that the temperature of the injected material is below the firing temperature of the firing head.

It is expedient if the material for encapsulation of the ignition head is applied simultaneously via two injection ports, which are arranged symmetrically to the firing head. By injecting the material of the envelope over two Anspritzkanäle it is ensured that there is no displacement of the ignition head in the mold during the introduction of the material. This ensures a uniform envelope of the ignition head.

Furthermore, it is favorable if after encapsulation of the ignition head another encapsulation, preferably with higher melting material, is carried out in the same injection mold. Since the ignition head is already protected during the second extrusion coating, one can work here with a relatively high temperature and / or with a relatively high pressure.

A further production method is characterized in that the firing head is complete and the terminal lugs, at least with the regions directly adjoining the latter, are transformed into a liquid hardening plastic, preferably a plastic, hardening plastic. 3 times latex, to be dipped. This results in the immersion in latex and the advantage of an elastic sheath.

A further production method, with which a largely uniformly thick sheathing can be achieved, is characterized in that the sheath is applied to the firing head and at least to the areas of the terminal lugs immediately adjacent to it in the fluidized bed process. In this case, the squib is heated and immersed in a powder bed made of plastic (^ fluidized bed). The plastic powder melts on the primer and forms a film on the surface. Upon cooling, a dense solid plastic layer forms.

The plastic layer can also be applied analogously to the method of classical powder coating by means of potential difference.

In all manufacturing processes, it is expedient if the terminal lugs are at least partially roughened before being enveloped. This results in the advantage of improved adhesion of the envelope on the ignition head, and in consequence a higher security against the ingress of moisture. The roughening can be done by embossing, sandblasting and other mechanical processes or by the use of plasma.

Alternatively or additionally, the terminal lugs and, if appropriate, the ignition head can be at least partially pretreated with an adhesion promoter prior to wrapping. This also improves the adhesion of the envelope to the terminal lugs. Due to the better adhesion of the envelope to the terminal lugs, the security against the ingress of moisture is further increased.

Especially in mass production, it is advantageous if the envelope is applied to a plurality of interconnected firing heads simultaneously. Thus, the production of the • · · · · · · · · · · · · ······················································································· It is very rational and rapid to use the igniter of the invention. In this case, the ignition heads can be arranged on strips, with which the pins are connected to each other, or even on a roll. In principle, it is also possible to provide the firing heads individually with a sheath.

In the detonators according to the invention, the ignition heads are very well protected against external influences, in particular moisture, and can be used in a further processing step, e.g. a Umspritzvorgang be provided with a voluminöseren sheath of plastic, wherein also booster material can be introduced. In this case, the envelope of the ignition head protects this from the temperature load of a further encapsulation and the injection pressure.

If the pill has a plastic clasp, the injection may terminate in front of the clasp or envelop it in whole or in part.

An igniter according to the invention is characterized in that the ignition head and the area of the terminal lugs adjoining it are encapsulated with a plastic layer. In this way, the moisture protection is sichergesteilt.

It is provided according to a further feature of the invention that the enclosure has a constriction in the region of the terminal lugs. This prevents a possible initiation of cracks in the plastic in the direction of the terminal lugs during ignition of the ignition head.

Suitable plastics for the cover are thermoplastics with low water absorption and water permeability, such as e.g. Polyolefins. In principle, however, it is also possible to use other plastics, provided that the processing temperature of the plastics is tolerated by the ignition head without damaging it. - 5 - • Μ · · «

If the wrapper is made of a resilient plastic, such as e.g. Made of rubber or silicone, there is the advantage that the envelope due to their elasticity can easily compensate for dimensional changes due to temperature fluctuations.

If the sheath consists of a thermosetting plastic, there results a thermally highly resilient sheath, which remains substantially stable up to its decomposition temperature.

The invention will now be explained in more detail with reference to the drawings. 1 shows a firing head according to the invention in section; FIG. 2 shows the firing head according to FIG. 1 in a sectional side view; FIG. 3 shows an axonometric representation of the ignition head; and Fig. 4 is a sectional view of a fuze with base.

The igniter according to the invention comprises a firing head 1 which is covered by a plastic sheath 2, e.g. a polyolefin, is surrounded. In this case, the firing head 1 is connected to terminal lugs 3, which are also surrounded by the enclosure 2, at least in their area immediately adjacent to the firing head 1.

In the region of the transition from the head 5 of the igniter to the enveloping of the terminal lugs 3, a constriction 4 is provided, is prevented by the ignition of the ignition head by an electrical pulse of a possible initiation of cracks in the plastic of the enclosure 2 in the direction of the lugs.

As can be seen from FIG. 4, contact pins 3 'can be held on a circuit board 8, which is encapsulated together with the ignition head 1. In the illustration of FIG. 4, the terminal lugs 3 (see FIG. 1) lie in front of and behind the plane of the drawing and are therefore not visible. But they are connected to the contact pins 3 '. 0 0 • • • 0 • 0 • 0 0 0 0 0 «0 0 0 0 • · 0 0 0 0 0 0 0 0 0 0 - 6 -

According to FIG. 4, a socket 7 is molded onto the igniter according to FIGS. 1 to 3. This base 7 has a circumferential groove 9, in which there may be an O-ring for sealing the propellant charge housing. In this way, the 5 squib is additionally protected, and it creates a sealed space in front of the squib, in which propellant protected against moisture can be installed.

Ml * f

Vienna, am

Claims (14)

Dr. Müllner Dipl.-Ing. Katschitik'ä CißG. ^ Aftffttanwaltskanzlei Weihburggasse 9, Postfactf * 15δ ·, · Α-Ί · 01 ^ ΑΑ / Γ6Ν * / isferreich Telephone: t +43 (1) 512 24 81 / Fax: ä + 43 (1) 513 76 81 / E-Mail: ® repatent@aon.at Account (PSK): 1480 708 BLZ 60000 BIC: OPSKATWW IBAN: AT19 6000 0000 0148 07081 480 708 MM / 41327 Hirtenberger Automotive Safety GmbH & Co KG A-2552 Hirtenberg (AT) Claims: 5 1. A method for producing a detonator for a pyrotechnic gas generator, in particular for airbags or belt tensioners, having a firing head (1) with terminal lugs (3), characterized in that the firing head (1) completely and the terminal lugs (3) at least with the immediately adjoining this areas in an injection mold and injected around. 10 2. The method according to claim 1, characterized in that the material for encapsulation of the ignition head (1) simultaneously via two Anspritzkanäle, which are arranged symmetrically to the firing head (1) is applied. 15 3. The method according to claim 1 or 2, characterized in that after encapsulation of the ignition head another encapsulation, preferably with higher melting material, is carried out in the same injection mold. 20 4. A method for producing a detonator for a pyrotechnic gas generator, in particular for airbags or belt tensioners having a firing head (1) with terminal lugs (3), characterized in that the firing head (1) and the terminal lugs (3) at least with be immersed in this directly adjoining areas in a liquid hardening plastic, preferably latex. 5. A method for producing a detonator for a pyrotechnic gas generator, in particular for airbags or 25 «· ··· · · · · · · · · · · · · · · · · • * * ··· «··· < ♦ · · · · · 9 · · · · · · · · · · · · · - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - characterized in that the sheath (2) is applied to the firing head (1) and at least to the immediately adjacent thereto areas of the terminal lugs (3) in the fluidized bed process. 6. A method for producing a detonator for a pyrotechnic gas generator, in particular for airbags or belt tensioners having a firing head (1) with terminal lugs (3), characterized in that the sheath (2) on the firing head (1) and at least which is applied to this immediately adjacent areas of the terminal lugs (3) in the powder coating process. 7. The method according to any one of claims 1 to 6, characterized in that the terminal lugs (3) are roughened before wrapping at least partially. 8. The method according to any one of claims 1 to 7, characterized in that the terminal lugs (3) and optionally the firing head (1) are pretreated before wrapping at least partially with a bonding agent. 9. The method according to any one of claims 1 to 8, characterized in that the sheath (2) is applied to a plurality of interconnected ignition heads (1) simultaneously. 10. igniter for a pyrotechnic gas generator, in particular for airbags or belt tensioners, the one Zündköpfchen / 1 \ tv »i + 7 \ v» n / ^ V »lv% / *» v · »/ O \ -> tt · Ρ tt λ - »r» + a «4« «\ ±) around nuoouiuooiaiuicii \ auiwcio l. / uauuj. Wu characterized in that the firing head (1) and at least the immediately adjacent to this region of the terminal lugs (3) is encapsulated with a plastic layer. ·· ♦♦ »· ► t · < · I • · • · ♦ - 3 - 11. igniter according to claim 10, characterized in that the sheath (2) has a constriction in the region of the terminal lugs (3). 5 12. igniter according to claim 10 or 11, characterized in that the sheath (2) made of a thermoplastic, preferably made of a polyolefin. An igniter according to claim 10 or 11, characterized in that the sheath (2) is made of an elastic plastic, e.g. Rubber or silicone, is made. 10 • e • • • • 4 • 1 4 • • • • • • • • ♦ · · · * ·· • · • «* · 14. igniter according to claim 10 or 11, characterized in that the sheath (2) consists of a thermosetting plastic. 0 b. Vienna, am