JP4248423B2 - Gas generator - Google Patents

Description

  The present invention relates to a gas generator suitable for inflating a side airbag, an air curtain, or the like.

  An air bag is known as one of safety devices for protecting an occupant from an impact generated when a car collides. This airbag operates with a large amount of high-temperature and high-pressure gas generated by a gas generator. 2. Description of the Related Art Conventionally, there are two known types of gas generators that generate gas. One is a pyro type that generates all the generated gas by combustion of a solid gas generating agent. The other is a hybrid system in which a large amount of high-temperature and high-pressure gas is released by a cylinder holding a high-pressure gas and a small amount of explosive composition for supplying heat to the high-pressure gas in the cylinder.

  In recent years, downsizing is one of the performances required for gas generators. In the former pyro type, it is necessary for the gas generating agent in the gas generator to increase the number of moles of gas generated by combustion in order to realize a reduction in size of the gas generator. As the gas generant composition for increasing the number of gas generating moles of the gas generant, a gas generant composition containing guanidine nitrate as a fuel and ammonium nitrate as an oxidizing agent is effective. For example, as described in Patent Document 1, a gas generant composition containing a guanidine derivative as a nitrogen-containing organic compound, a phase-stabilized ammonium nitrate as an oxidizing agent, a pressure index regulator, and a silicon compound as a detonation inhibitor, respectively. Is disclosed. However, since the guanidine derivative and ammonium nitrate are contained in a large amount, the combustion rate is low, and in order to obtain sufficient combustion performance in the gas generator, it is necessary to burn the gas generating agent under higher pressure. Moreover, since the internal pressure at the time of operation of the gas generator increases, the gas generator needs to have higher strength and is increased in size.

  Furthermore, in the case of a gas generant composition containing a low-reactivity raw material such as guanidine derivative or ammonium nitrate as a composition, the low ignitability of the gas generant is one of the problems as well as the slow combustion rate. The air bag takes about 30 to 60 ms from the start of operation until the air bag is deployed, and even a slight operation delay of the gas generator has a great influence and cannot exert sufficient performance. When the ignitability of the gas generating agent is low, even if the igniter in the gas generator ignites, it takes a long time to ignite the gas generating agent, resulting in a delay in ignition of the gas generator. Although the ignition delay can be improved to some extent by increasing the amount of the charge transfer agent in the gas generator, the amount of heat transfer charge increases, so the total heat generation amount of the gas generator itself increases. The weight of the filter member increases and the gas generator becomes larger.

  On the other hand, the hybrid system is suitable for miniaturization because a small amount of gas generating agent is required. However, because of the need to hold the gas in the cylinder under high pressure, the high-pressure gas may generally escape from the cylinder over the life of 15 years as a gas generator and may not be able to exhibit sufficient performance. is there. For this reason, since it is necessary to seal the gas in the cylinder over a long period of time, it is necessary to seal the cylinder with a rupture disk having high mechanical fracture strength and high sealing performance. An example of this type of gas generator is disclosed in Patent Document 2. This gas generator uses a rupture diaphragm (rupture disk) with high fracture strength to enhance the gas tightness of the first container (cylinder) in which high-pressure gas is sealed, and the rupture diaphragm has a combustion chamber or the like. The hollow piston provided in the second container provided with the above is pushed forward by the ignition of the propulsion charge (igniter) to surely rupture the rupture diaphragm of the first container, and the high pressure gas in the first container is It is surely released. Thus, although the rupture diaphragm can be surely destroyed, there is a problem that the structure of the gas generator becomes complicated because it is necessary to install a hollow piston or the like.

  Further, the destruction of the rupture disk that reliably seals the cylinder is not destroyed by using a hollow piston or the like as disclosed in Patent Document 2, but the pressure in the combustion chamber including the igniter is increased by increasing the amount of the transfer agent. There is also a thing which raises and destroys. However, in order to increase the amount of the transfer agent, a room for storing the transfer agent is required, and it is difficult to downsize the gas generator. In this case, it is also difficult to destroy the rupture disk simultaneously with the ignition of the igniter.

  In this type of gas generator, the high-pressure gas in the cylinder is adiabatically expanded and ejected from the cylinder. Therefore, it is necessary to heat and release the gas. There was also a problem that it could not be heated sufficiently.

  In addition, the thin film bridge used in the igniter described in Patent Document 3 is exposed to a high temperature and may be damaged by heat and may not operate normally. In addition, when bonded with conductive epoxy resin, when used as an igniter such as a gas generator for automobiles, it will be exposed to high temperature heat generated under the hot summer heat for a long time. The resistance value of may change. Further, even at the beginning of assembly, the resistance value is easily influenced by the state of the electrode surface, and there is a problem that the initial resistance value varies greatly. Also, in the case of wire bonding, the problems of solder and conductive epoxy resin can be solved, but since the thin film bridge is fixed in a state protruding from the embolus, the pressing force can be applied when loading explosives. If this occurs, there is a risk of disconnection. In particular, in the case of so-called standing, which is described in Patent Document 3 in which the end surfaces of the wires are erected and joined, the risk becomes significant.

  Patent Document 4 discloses a hybrid system in which a large amount of high-temperature and high-pressure gas is released by a cylinder holding high-pressure gas and a small amount of explosive composition for supplying heat to the high-pressure gas in the cylinder. There is a disclosure of a gas generator.

JP 11-292678 A JP-A-8-253100 US Pat. No. 6,324,979B1 International Publication No. WO02 / 062629 Pamphlet

  The object of the present invention is that it is possible to inflate an air bag in a short time compared to a conventional gas generator, and at the same time satisfies the miniaturization and simplification of the structure, and warms the gas from the high pressure gas cylinder. It is another object of the present invention to provide a hybrid gas generator that can be released.

  In order to solve the above problems, a gas generator according to the present invention includes a cylinder, a housing in which a transfer charge and an igniter are accommodated, a rupture disk that holds and seals the pressure of the cylinder, and the cylinder and the housing. An outer cylinder material that connects and holds the cylinder and the housing so as to form a gas retention space between the filter and a filter material provided along an inner periphery of the outer cylinder material, The igniter includes an embolus having at least two electrode pins insulated from each other, and a thin film bridge attached to the embolus, and supplies current to the thin film bridge through the electrode pin. A gas generator that is activated to ignite explosives, wherein the thin film bridge is substantially flush with a head portion of the electrode pin and a header portion of the embolus. Embedded in a recess provided in the embolus, and the thin film bridge is connected to the electrode pin by wire bonding, and one of the electrode pads of the thin film bridge is bonded to a metal part of the header portion of the embolus by wire bonding It is characterized by being connected.

  The gas generator according to the present invention is characterized in that an outer diameter B of the cylinder is in a range of 20 mm to 30 mm.

  In the gas generator according to the present invention, the thin film bridge is connected by using the peripheral surface of the wire in a state where the wire is laid down, not by so-called standing, which is connected at the end face of the wire, and the thin film bridge. Even when the electrode pin and the electrode pin are connected by wire bonding, the wire loop height can be kept low. For this reason, even if it is a case where the pressure which presses against a wire part acts, it becomes possible to prevent a disconnection of a wire. Since at least one of the electrode pads is connected to the header metal portion of the embolus by wire bonding, malfunction of the thin film bridge due to static electricity or the like can be prevented. And since the thin film bridge is used for the ignition part of the igniter, the ignition time is about 1/10 faster than the conventional bridge type igniter, and the electric energy at the time of ignition is about 1 / As low as 25, it becomes possible to ignite explosives stably at high speed and low energy.

  In the gas generator according to the present invention, it is preferable that the rupture disk is broken by a flame force from the igniter.

  While simplifying the structure of a gas generator, it becomes possible to reduce in size. Moreover, the adiabatic expansion gas ejected from the cylinder can be heated more efficiently.

  In the gas generator according to the present invention, the material of the surface of the electrode pad of the thin film bridge is preferably gold, aluminum, nickel, or titanium.

  Since the material of the electrode pad surface of the thin film bridge is any one of gold, aluminum, nickel, and titanium, the current is reliably supplied to the thin film bridge by being connected to the electrode pin by wire bonding.

  In the gas generator according to the present invention, it is preferable that the wire used for the wire bonding is gold or aluminum and the wire diameter is 10 μm to 500 μm.

  Since the wire used for wire bonding is gold or aluminum, it is possible to reliably supply current from the electrode pin to the thin film bridge. Further, by setting the wire diameter to 10 μm to 500 μm, preferably 20 μm to 500 μm, and more preferably 100 μm to 500 μm, it becomes possible to more reliably supply current from the electrode pin to the thin film bridge.

  The gas generator according to the present invention preferably further has a wire bonding wire loop height (h3) of 1 mm or less.

  Since the wire loop height is 1 mm or less, preferably 0.5 mm or less, more preferably 0.2 mm or less, it prevents wire breakage even when stress is applied to the wire during loading of explosives, etc. can do.

  Further, the gas generator according to the present invention is preferably one in which a plurality of second flame discharge holes directed to the outer cylinder material are formed in the side cylinder portion on the bottom side of the housing.

  Since a plurality of second flame discharge holes are formed in the side tube portion of the housing, flame or hot gas is discharged from the second flame discharge holes into the gas retention space. And the gas in gas retention space can be stirred. For this reason, the cold gas discharged | emitted from the cylinder is heated by the heat flow from a housing, and comes to be discharged | emitted from the gas discharge hole provided in the outer cylinder material.

  The gas generator of the present invention is configured as described above, and uses an igniter in which a thin film bridge is embedded in an embolus and is placed so as to be substantially flush with the head of the electrode pin and the header of the embolus. Thus, the explosive can be ignited in a stable state with high speed and low energy. For this reason, the effect of being able to inflate and deploy the airbag in a short time, which is a feature of the hybrid gas generator, can be obtained more remarkably.

  An example of an embodiment of a gas generator according to the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view of an example of an embodiment of a gas generator according to the present invention. In FIG. 1, the gas generator P <b> 1 includes a cylinder 1 in which high-pressure gas is stored, a housing 4 in which a transfer charge 2 and an igniter 3 are stored, and an outer cylinder member 5 that holds and connects the cylinder 1 and the housing 4. The filter member 10 is provided along the inner periphery of the outer cylinder member 5.

  The cylinder 1 is made of a metal such as stainless steel or aluminum, has a bottomed cylindrical shape, and the opening side is reduced in diameter in two stages. The cylinder 1 is loaded with a sufficient amount of argon or helium gas or the like to inflate and actuate the airbag or the like (for example, 0.8 to 1.2 moles in the air curtain), and the pressure is 20 MPa or more. The opening on one end side is preferably sealed with a cylinder cap 23 having a rupture disk 6. The outer diameter B of the cylinder 1 is preferably in the range of 20 mm to 30 mm.

  The thickness of the rupture disk 6 is not particularly limited as long as it can be broken by the igniter 3. The thickness of the rupture disk 6 is preferably in the range of 0.05 to 0.5 mm, more preferably in the range of 0.1 to 0.3 mm.

  The housing 4 has a cup shape and includes a bottom portion 7 and a side tube portion 8. In the housing 4, a stepped portion 11 is formed on the outer peripheral portion of the side tube portion 8. A first flame discharge hole 13 that opens from the inside of the combustion chamber 12 toward the outside is formed in the bottom portion 7. The first flame discharge hole 13 is reduced in diameter from the combustion chamber 12 toward the outside. As a result, the flame power is increased and the emitted flame can be concentrated at the center of the rupture disk 6. Although not shown, a metal seal tape made of aluminum or the like is attached to the bottom 7 side of the first flame discharge hole 13. This seal tape prevents moisture and the like from entering the combustion chamber 12 and prevents the transfer charge 2 stored in the combustion chamber 12 from getting wet. Further, the thickness of the seal tape is preferably 100 μm or less, and is melted instantaneously by the flame generated by ignition of the igniter 3 and does not hinder the progress of the flame. A plurality of second flame discharge holes 30 facing the outer cylinder material 5 are formed in the side cylinder portion 8 of the housing 4. Therefore, the flame from the igniter 3 is emitted from the first flame emission hole 13 and the second flame emission hole 30 without being obstructed by the obstacle in the combustion chamber 12. A plurality of the second flame discharge holes 30 are usually formed, and preferably four are formed at equal intervals in the same circle.

  As shown in FIG. 1, the charge 4, the first cushion material 14, the second cushion material 15, and the holder 20 are loaded in the housing 4 in this order. The igniter 3 is caulked and fixed to the holder 20. These are fixed by bending the open end 21 of the housing 4 inward and pressing the holder 20. The transfer charge 2 is usually donut-shaped (hollow cylindrical shape). A central space in the housing 4 formed by the charge transfer agent 2, the first cushion material 14, and the second cushion material 15 forms a combustion chamber 12. The first cushion material 14 and the second cushion material 15 are made of ceramic fiber, silicon foam, or the like, and are formed in a donut shape like the transfer charge 2. These first cushion material 14 and second cushion material 15 absorb vibration transmitted to the charge transfer agent 2 so that the transfer charge 2 is not crushed by vibration or the like. The transfer charge 2 may be used by laminating one or more transfer charges formed in a donut shape, and a smaller-diameter granular transfer charge may be arranged in a donut shape via a support member.

  As shown in FIG. 2, the igniter 3 includes an embolus 34 having a pair of mutually insulated electrode pins 32 and 33, and a thin film bridge 35 attached to the embolus 34. A current is supplied to the thin film bridge 35 through the electrode pins 32 and 33, and the thin film bridge 35 is operated to ignite the explosives 36 and 37 loaded in the first tubular body 39.

  The embolus 34 is made of a metal such as stainless steel, aluminum, copper, or iron. Further, the pair of electrode pins 32 and 33 extending from the embolus 34 is formed of a metal such as stainless steel, aluminum, copper, iron, etc., like the embolus 34. The electrode pins 32 and 33 are covered with an insulator 41 such as glass or resin in the embolus 34 and insulated from each other. The heads 45 of the electrode pins 32 and 33 are provided so as to be substantially flush with the header portion 54 of the embolus 34.

  FIG. 3 is an enlarged plan view of the portion where the thin film bridge 35 of FIG. 2 is embedded in the recess 42 of the embolus 34 as viewed in the direction C. FIG. 4 is a cross-sectional view taken along line A-A ′ in FIG. 3. FIG. 5 is a view showing a cross section taken along line B-B ′ in FIG. 3.

  As shown in FIGS. 3, 4, and 5, the thin film bridge 35 is embedded in a recess 42 formed in the embolus 34, and is substantially flush with the header portion 54 of the embolus 34 and the head 45 of the electrode pins 32 and 33. It is installed to become. As shown in FIG. 4, the recess 42 has a groove depth h1 of usually more than 0.2 mm and 1 mm or less, preferably more than 0.2 mm and 0.75 mm or less, more preferably more than 0.2 mm and 0.5 mm. Therefore, when the thin film bridge 35 is embedded, the step h2 of the electrode pins 32 and 33 with the head 45 is set to 1 mm or less, preferably 0.5 mm or less, more preferably 0.2 mm or less. The wire bonding loop height h3 can be lowered. Moreover, as shown in FIG.4 and FIG.5, what is called horizontal attachment which connects using the surrounding surface of the wire 38 in the state which laid down the wire 38 can be performed easily. Thus, since the loop height h3 of the wire 38 is usually 1 mm or less, preferably 0.5 mm or less, and more preferably 0.2 mm or less, the wire 38 is subjected to a pressing pressure when charged with explosives or the like. However, disconnection of the wire 38 can be prevented, and the electrode pins 32 and 33 and the thin film bridge 35 can be reliably connected. The wire 38 is preferably gold or aluminum. This makes it possible to reliably supply current from the electrode pins 32 and 33 to the thin film bridge 35. The wire 38 has a wire diameter of usually 10 μm to 500 μm, preferably 20 μm to 500 μm, and more preferably 100 μm to 500 μm, so that the current can be supplied from the electrode pins 32 and 33 to the thin film bridge 35 more reliably. It becomes.

  As shown in FIG. 3, the thin film bridge 35 and the wire 38 that joins the electrode pins 32 and 33 are connected so as to span the surface of the electrode pad 51 of the thin film bridge 35. At this time, as described above, because the thin film bridge 35, the header portion 54 of the embolus 34, and the head portions 45 of the electrode pins 32 and 33 are disposed in the concave portion 42 of the embolus 34 (see FIG. 2, see FIG. 4), the wire 38 can be bonded to the electrode pad 51 of the thin film bridge 35 in a so-called lateral manner. In addition, by connecting the wire 38 from one electrode pad 51 to the metal portion of the header portion 54 of the embolus 34, it is easy to ground. In addition, the electrode pad 51 wire-bonded to the electrode pins 32 and 33 by the wire 38 is a laminated body 53 in which a reactive metal such as titanium and a reactive insulator such as boron are alternately laminated. It is made of gold, aluminum, nickel, titanium or the like formed on the surface by thermal evaporation or the like. In addition to titanium, reactive metals include aluminum, magnesium, zirconium and the like. In addition to boron, the reactive insulator includes calcium, manganese, silicon, and the like.

The thin film bridge 35 can be any of a heating resistor, a reactive bridge using a reactive substance, a shock bridge, and the like. It, LIGA the Si substrate, Al ₂ O _3, or the like of the ceramic substrate (Lithographie Galva-noformung, Abfprmung (micro electro mechanical system) utilizing X-ray) and processes, is formed by known techniques such as sputtering. In particular, the reactive bridge is preferable in that it operates stably with small energy.

  As shown in FIGS. 4 and 5, the reactive thin-film bridge 35 shown in this embodiment includes a reactive metal formed on the surface of the substrate 52, such as titanium, and a reactive insulator, such as boron. And the like, and the electrode pad 51 formed of a conductive material such as a metal covering the surface of the bridge. 3, 4, and 5, the electrode pad 51 is positioned on the stacked body 53.

  Examples of reactive metals used for the laminate 53 include aluminum, magnesium, zirconium, and the like in addition to titanium. In addition to boron, the reaction insulator includes calcium, manganese, silicon, and the like. When the thin film bridge 35 having such a laminated body 53 is activated when a current flows through the bridge portion, the reactive metal reacts with the reactive insulator and is released as hot plasma. And this plasma can ignite the loaded explosive efficiently.

The igniter 3 shown in FIG. 2 according to this embodiment is manufactured as follows.
First, the explosives 36 and 37 are loaded into the first tube 39. The thin film bridge 35 is installed in the recess 42 formed in the embolus 34. The electrode pins 32 and 33 and the thin film bridge 35 are connected by wire bonding using a wire 38. The embolus 34 and the first tube 39 are fitted. At this time, even if the embolus 34 is pressed against the explosive 36 side, the thin film bridge 35 is embedded in the embolus 34 as described above, and the electrode pins 32, Since it is connected to 33, there is no fear of disconnection or the like. In this way, after the embolus 34 is fitted to the first tubular body 39, the first tubular body 39 is inserted into the second tubular body 29. Then, insert molding is performed so as to be integrated with the igniter holder 28. Thus, it can be suitably used for an igniter for a gas generator used for various safety devices such as automobiles.

  In the igniter 3 configured as described above, when the current is supplied to the electrode pins 32 and 33, the thin film bridge 35 is operated, and the speed is about 1/10 that of the conventional bridge line. It becomes possible to ignite the explosives 36 and 37 efficiently in units of several μsec. In addition, since the explosive can be efficiently ignited by the thermal energy generated in the thin film bridge 35, variations such as ignition delay can be reduced.

  The igniter 3 is not limited to the above-described embodiment, and can reliably connect the electrode pins 32 and 33 and the thin film bridge 35 by wire bonding. An ASIC (Application Specific Integrated Circuit) or the like may be interposed between either one of the thin film bridges 35 and similarly connected by wire bonding.

  As shown in FIG. 1, the igniter 3 is arranged coaxially with the housing 4 and has a structure facing the first flame discharge hole 13 formed in the bottom portion 7. A plurality of second flame discharge holes 30 facing the outer cylinder material 5 are formed in the side cylinder portion 8 of the housing 4. Therefore, the flame from the igniter 3 is emitted from the first flame emission hole 13 and the second flame emission hole 30 without being obstructed by the obstacle in the combustion chamber 12.

  The igniter 3 preferably has an internal pressure increase of 4.7 MPa or more within 3 milliseconds when ignited in a 10 cc tank. Thereby, the rupture disk 6 can be reliably broken by the flame force.

As the explosives 36 and 37 loaded in the igniter 3 in order to generate such flame power, it is preferable that zirconium (Zr), tungsten (W), and potassium perchlorate (KClO ₄ ) are contained as components. It is preferable to use a binder using fluororubber or nitrocellulose as a binder. The composition ratio (weight ratio) of zirconium, tungsten, and potassium perchlorate is determined so that the thin film bridge 35 of the igniter 3 can be sufficiently ignited, and Zr: W: KClO ₄ = 3: 3.0. ˜4.0: 3.0 to 4.0 is preferable, and Zr: W: KClO ₄ = 3: 3.5: 3.5 is more preferable.

  As the explosive charge 2, for example, boron, potassium nitrate, 5-aminotetrazole, lead-free explosives, etc. can be used so that the calorific value is 4000 J / g or more, preferably 5500 J / g or more. By setting it as such a composition, it becomes possible to make calorific value 4000 J / g or more, preferably 5500 J / g or more. Here, in the case of an explosive with a calorific value of less than 4000 J / g, the rupture disk 6 that seals the cylinder 1 is ruptured, and the heated gas can be sufficiently heated when the temperature of the released gas is lowered due to adiabatic expansion. It becomes difficult. For this reason, it is necessary to increase the amount of the explosive charge 2, and the gas generator P1 cannot be reduced in size.

  As shown in FIG. 1, the outer cylinder member 5 is preferably formed in a cylindrical shape by a metal material such as stainless steel or aluminum, and a stepped portion formed in the housing 4 by fitting the housing 4 on one end side. 11 is fixed by caulking. The other end side of the outer cylinder member 5 is fitted in contact with the first step portion 19 of the cylinder 1 having a reduced diameter, and is welded and fixed by welding or the like. A gas retention space 16 is formed between the rupture disk 6 and the bottom 7 of the housing 4. A filter material 10 is disposed on the outer peripheral portion of the gas retention space 16, that is, on the inner peripheral portion of the outer cylinder material 5.

  The filter material 10 is formed into a cylindrical shape having an outer diameter substantially the same as the inner diameter of the outer cylinder material 5 by an aggregate of knitted wire mesh, plain weave wire mesh, or crimp woven metal wire material, for example. Gas discharge holes 17 are formed at predetermined intervals around the outer cylinder material 5 at a portion where the filter material 10 abuts. Further, the filter material 10 is installed so that the inner peripheral portion thereof is in contact with the outer periphery of the cylinder cap 23, is spanned from the cylinder 1 to the housing 4, and covers the gas retention space 16. As a result, all the gas from the cylinder passes through the filter material 10 and is discharged from the gas discharge hole 17.

  Thus, since the cylinder 1 and the housing 4 are fitted and fixed by the outer cylinder member 5 made of the same cylinder, the cylinder 1 and the housing 4 are connected and held on the same axis with the respective axes aligned. As a result, the center of the igniter 3, the first flame discharge hole 13, and the rupture disk 6 are coaxial, and the flame from the igniter 3 strikes the center of the rupture disk 6 in a concentrated manner.

  Further, since the filter material 10 is provided so as to cover the outer periphery of the gas retention space 16 formed between the cylinder 1 and the housing 4, the gas from the cylinder 1 and the housing 4 are separated in the gas retention space 16. The hot gas is efficiently mixed and discharged from the gas discharge hole 17.

  Next, the operation of the gas generator P1 will be described with reference to FIG. In addition, the gas generator P1 shown in FIG. 1 shall be directly or indirectly connected to the airbag apparatus on the shaft end side on the housing 4 side.

  When the collision sensor detects an automobile collision, the gas generator P1 causes the igniter 3 to energize and ignite as shown in FIG. The flame of the igniter 3 ruptures the end face 24 and is ejected into the combustion chamber 12 from the center of the end face 24 of the igniter 3. The flame that has passed through the combustion chamber 12 is enhanced in flame power by the restriction of the first flame discharge hole 13 and the second flame discharge hole 30, and a metal seal tape provided at the outlet of the first flame discharge hole 13 is used. It melts instantly, hits the center of the rupture disc 6 intensively, and bursts the rupture disc 6 at once. The gas discharged from the rupture disk 6 flows out from the first flame discharge hole 13 and the second flame discharge hole 30 to the gas retention space 16. At this time, the released gas undergoes adiabatic expansion in the gas retention space 16, and thus the temperature rapidly decreases. At this time, the gas released from the cylinder 1 is temporarily released into the gas retention space 16 without being discharged from the gas discharge hole 17 at once because of the filter material 10 provided around the gas retention space 16. Stay. And it mixes with the hot gas from the igniter 3 mentioned later, and is heated. Further, since the second flame discharge hole 30 is formed facing the outer cylinder member 5, first, the released heat flow hits the inner wall of the filter member 10 and the outer cylinder member 5, and agitates the gas in the gas retention space 16. . For this reason, the gas in the gas retention space 16 can be reliably heated and released from the gas discharge hole 17.

  On the other hand, the transfer charge 2 in the combustion chamber 12 is burned by the flame from the igniter 3. The high-temperature heat flow generated thereby flows into the gas retention space 16 and mixes with the low-temperature gas released from the cylinder 1. The gas released from the cylinder 1 is heated thereby, becomes high-temperature gas, passes through the filter material 10, and is released from the gas discharge holes 17 formed in the outer cylinder material 5. Thus, the airbag connected to the gas generator P1 is instantly inflated by the clean gas discharged from each gas discharge hole 17.

  Thus, according to the gas generator P1 of the present invention, since the calorific value of the charge transfer agent 2 is preferably 4000 J / g or more, more preferably 5500 J / g, the loading amount of the transfer charge 2 can be reduced, The combustion chamber 12 can be reduced in size. As a result, the distance between the rupture disk 6 and the igniter 3 can be shortened, and the flame of the igniter 3 is directly applied to the rupture disk 6 by making the rupture disk 6 and the igniter 3 face each other. Can do. For this reason, the capacity of the combustion chamber is reduced compared to the conventional case where the rupture disk is destroyed by increasing the pressure in the combustion chamber with the gas generated by burning the transfer charge stored in the combustion chamber. Can be realized.

  Further, since the first gas discharge hole 13 is formed in the bottom portion 7 of the housing 4 so that the flame generated in the igniter 3 strikes the center of the rupture disk 6 in a concentrated manner, Even when the rupture disk 6 having high mechanical strength is used by a flame without using mechanical means such as the above, it can be surely ruptured. For this reason, the structure of the gas generator P1 can be simplified.

  Further, since the filter material 10 is provided so as to cover the gas retention space 16 formed between the cylinder 1 and the housing 4 from the cylinder 1 to the housing 4, the filter material 10 is ejected from the cylinder 1 and adiabatically expands. The gas can be efficiently heated with the high-temperature gas from the igniter 3.

The gas generator P1 of the present invention is a hybrid gas generator suitable for inflating a side airbag, an air curtain, or the like.
The gas generator P1 of the present invention can be used not only as an airbag but also as a safety switch for disconnecting the vehicle power supply from the vehicle battery in the event of an accident triggering the safety system, such as a seat belt pretensioner. can do.

It is sectional drawing of an example of embodiment of the gas generator concerning this invention. It is sectional drawing of an example of the igniter used for the gas generator concerning this invention. It is a figure which shows the principal part plane which expanded a part of FIG. It is a figure which shows the A-A 'line cross section in FIG. It is a figure which shows the B-B 'line cross section in FIG.

Explanation of symbols

P1 gas generator B outer diameter h1 groove depth h2 step h3 loop height 1 cylinder 2 transfer powder 3 igniter 4 housing 5 outer cylinder material 6 rupture disk 7 bottom 8 side cylinder 10 filter material 11 stepped part 12 Combustion chamber 13 First flame discharge hole 14 First cushion material 15 Second cushion material 16 Gas retention space 17 Gas discharge hole 19 First stage portion 20 Holder 21 Open end 23 Cylinder cap 24 End face 28 Igniter holder 29 First 2 pipe 30 second flame discharge hole 32 electrode pin 33 electrode pin 34 embolus 35 thin film bridge 36 explosive 37 explosive 38 wire
39 First tube 41 Insulator 42 Recess 45 Head 51 Electrode pad 52 Substrate 53 Laminate 54 Header

Claims (7)

A cylinder (1), a housing (4) in which a charge transfer powder (2) and an igniter (3) are housed, a rupture disk (6) for holding and sealing the pressure of the cylinder (1), and the cylinder ( An outer cylinder member (5) for connecting and holding the cylinder (1) and the housing (4) so as to form a gas retention space (16) between 1) and the housing (4), and the outer cylinder A filter material (10) provided along the inner periphery of the material (5), and the igniter (3) includes at least two electrode pins (32, 33) insulated from each other. And a thin film bridge (35) attached to the embolus (34) for supplying a current to the thin film bridge (35) through the electrode pins (32, 33). Fire (35) (36, 37) A gas generator for igniting the (1),
The thin film bridge (35) is provided on the embolus (34) so as to be substantially flush with the head portion (45) of the electrode pin (32, 33) and the header portion (54) of the embolus (34). Embedded in the recess (42)
Furthermore, the thin film bridge (35) is connected to the electrode pins (32, 33) by wire bonding,
One of the electrode pads (51) of the thin film bridge (35) is connected to the metal part of the header part (54) of the embolus (34) by wire bonding.   The gas generator according to claim 1, wherein an outer diameter B of the cylinder (1) is in a range of 20 mm to 30 mm.   The gas generator according to claim 1 or 2, wherein the rupture disk (6) is broken by a flame force from the igniter (3).   The gas generator according to any one of claims 1 to 3, wherein a material of the surface of the electrode pad (51) of the thin-film bridge (35) is gold, aluminum, nickel, or titanium.   The gas generator according to any one of claims 1 to 4, wherein the wire (38) used for the wire bonding is gold or aluminum and has a wire diameter of 10 µm to 500 µm.   The gas generator according to any one of claims 1 to 5, wherein a loop height (h3) of the wire (38) of the wire bonding is 1 mm or less.   The plurality of second flame discharge holes (13) directed to the outer cylinder member (5) are formed in the side tube portion (8) on the bottom (7) side of the housing (4). The gas generator as described in any one of Claims.

Images