JP4593944B2 - Gas generator for airbag - Google Patents

Description

The present invention relates to a gas generator for an air bag suitable for inflating a side air bag 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 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 each cylinder (for example, Patent Document 1). The other is a pyro type that generates all the generated gas by burning a solid gas generating agent (see, for example, Patent Document 2).

  As an igniter used to ignite explosives, a thin-film bridge formed on a substrate such as ceramics is fixed to the embolus with epoxy resin, polyimide, ceramics, or the like. And this bridge has what is electrically joined with the electrode pin provided in the embolus with solder, wire bonding, conductive epoxy resin, etc. (for example, refer to patent documents 3). Among these, the solder contains lead that leads to environmental pollution. Moreover, it is necessary to melt the solder at a high temperature.

Moreover, in patent document 4, in order to make a housing and a partition member airtight reliably, the gas generator which has the partition member which notched the outer peripheral end surface of the partition member and provided seal members, such as an O-ring, is disclosed. There is.
JP-A-8-253100 JP 2000-203372 A US Pat. No. 6,324,979B1 International Publication No. 01/74633 Pamphlet

In recent years, downsizing and low cost can be given as performance required for gas generators for airbags . For example, since the thing of patent document 1 is a hybrid system, two chambers, a gas filling chamber and an explosive composition chamber, are required, and it enlarges and a weight increases. In addition, the welding structure is mainly used, which increases the cost. Moreover, since the gasification rate of a gas generating agent is also low, the amount described in Patent Document 2 requires a large amount of gas generating agent. In addition, it is separated from the enhancer chamber, gas generating agent chamber, and filter chamber, increasing the size and weight. In addition, the number of parts increases and the cost increases.

In general, the gasification rate of the gas generating agent and the heat generation amount are greatly related to the downsizing of the gas generator for an air bag . When the gasification rate is low, the weight of the gas generating agent increases. Moreover, when the calorific value increases, the weight of the filter increases, both of which lead to an increase in size and weight. In this regard, the pyro-type gas generator as described in Patent Document 2 has a gasification rate without increasing the filling amount of the gas generating agent by devising the composition of the gas generating agent to be filled. It is easy to reduce the size as compared with the hybrid system described in Patent Document 1 and the like.

However, as disclosed in Patent Document 2, the pyro type gas generator has a long and thin cylindrical housing, and has a structure in which sealing members are assembled to both ends by welding or the like. For this reason, it has been necessary to increase the thickness of the housing in order to improve the pressure resistance of the housing as the gasification rate and the heat generation amount increase. Also, due to the increase in the amount of heat generated, it is necessary to enlarge the filter material in order to sufficiently cool the gas, and it has not yet been possible to reduce the size and weight of the gas generator for airbags .

  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.

  Moreover, in the gas generator of patent document 4, the process of notching the outer peripheral end surface of a partition member and providing seal members, such as an O-ring, requires the problem that the manufacturing cost of a gas generator becomes high. There was a point. Further, in the gas generator described in Patent Document 4, the partition member does not partition the filter chamber and the combustion chamber.

Furthermore, the gas generator for an air bag used for a side (side impact) air bag needs to inflate the air bag faster because the distance between the door portion from which the air bag comes out and the occupant is reduced. . That is, the airbag deployment performance that is faster than the driver's seat and the passenger seat is required.

The present invention has been made in view of the above problems, smaller, lighter, with cost reduction is possible, for an air bag which can be ignited in a short time as compared with the conventional gas generator An object is to provide a gas generator.

The gas generator for an air bag according to the present invention for solving the above problems includes a combustion chamber filled with a gas generating agent that generates high-temperature gas by combustion in a cylindrical housing, and a filter in which a filter material is mounted. And an igniter for igniting and burning the gas generating agent in the combustion chamber, wherein the igniter has at least two plugs having insulated electrode pins, and a thin film bridge attached to the plug A gas generator for an air bag that supplies current to the thin film bridge through the electrode pin and activates the thin film bridge to ignite explosives, the thin film bridge being a head of the electrode pin and the step of the header portion of the emboli is embedded in a recess provided in said embolic so that 1mm or less, the thin film bridge, Wai of the electrode pin and alongside It is connected by chromatography bonding, one electrode pad of the thin film bridge, and is characterized in that it is connected by wire bonding alongside the metal portion of the header portion of the emboli.

In the gas generator for an air bag according to the present invention, the cylindrical housing preferably has an outer diameter B of 30 mm or less, and the igniter is attached to an end of the housing. Is.

In the gas generator for an air bag according to the present invention, the thin film bridge is not connected so as to be connected at the end face of the wire, but is connected so that the wire is laid down using the peripheral surface of the wire while being laid down. Even when the thin film bridge and the electrode pin are connected by wire bonding, the wire loop height can be suppressed to be 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 metal portion of the embolic header portion by lateral 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.

The conventional gas generator has a structure having a total of five parts such as a housing, a cover at its end, a cover at the other end, and an end, and a sealant (O-ring, etc.) at the other end. In the gas generator for an air bag according to the present invention, since the bottom end of the housing is closed and the end is open, it has three parts, and the number of parts can be reduced. In addition, reducing the number of parts also reduces the assembly process, thereby reducing the manufacturing cost. And it becomes possible to miniaturize the gas generator for airbags .

In the gas generator for an air bag according to the present invention, the material of the electrode pad surface 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 for an air bag according to the present invention, the wire used for the wire bonding is preferably gold or aluminum and has a wire diameter of 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 for an air bag according to the present invention preferably further has a 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, wire breakage is prevented even when pressing stress is applied to the wire during loading of explosives, etc. can do.

Moreover, the gas generator for an air bag according to the present invention preferably has a first partition member that partitions the combustion chamber and the filter chamber in which the filter material is mounted.

  By providing the first partition member, the filter material and the gas generating agent chamber (combustion chamber) are divided into two chamber structures to prevent damage (melting) of the filter due to the combustion heat of the gas generating agent.

In the gas generator for an air bag according to the present invention, the other end of the housing has a bowl shape or a flat bottom shape.

Since the other end portion of the housing has a bowl shape or a flat bottom shape, it can sufficiently withstand even when the pressure in the housing is increased. Further, since the end portion is closed in this way, it is only necessary to seal the other end portion, the number of parts can be reduced, and the sealing portion can be made only at one end of the other end portion. As a result, the safety of the gas generator for an air bag can be increased and the size can be reduced. In this housing, the ratio between the thickness of the cylindrical portion and the outer diameter is preferably in the range of 1.9 to 10.7, and preferably in the range of 3 to 6.8.

In the gas generator for an air bag according to the present invention, the enhancer agent is further filled in the combustion chamber.

By doing so, it is not necessary to fill the enhancer agent in another container and incorporate it into the gas generator for the air bag , thereby reducing the manufacturing cost and reducing the size of the air gas generator for the air bag .

In the gas generator for an air bag according to the present invention, the gas generating agent and the enhancer agent are directly filled in the combustion chamber without putting them in a container, and the gas generating agent and the enhancer agent are secondly added. It is separated by a partition member.

Since the enhancer agent and the gas generating agent are adhered via a second partitioning member, since the difference in distance between the enhancer agent and the gas generating agent due to the difference in the filling status of the gas generating agent does not occur, the gas for an air bag The performance of the generator can be stabilized.

In the gas generator for an air bag according to the present invention, the peripheral surface of the first partition member is caulked in a direction in which the peripheral surface of the housing contracts in diameter at each of two positions sandwiching the first partition member. The end surface is fixed so as to be hard to the inner peripheral surface of the housing .

This eliminates the need for a process of notching the outer peripheral end face of the conventional partition member and mounting a seal material such as an O-ring, so that the partition member and the housing are securely fixed at low cost. Therefore, it becomes possible to obtain a gas generator for an air bag having high airtightness.

The gas generator for an air bag according to the present invention is configured as described above, and an igniter in which a thin film bridge is embedded in an embolus and is disposed so as to be substantially flush with an electrode pin head and an embolus header. Can be used to ignite explosives at high speed and low energy. Further, since the structure is simple, it is possible to reduce the size and manufacture at a low cost.
Moreover, since the gas generator for airbags of this invention has the igniter containing a specific thin film bridge, when it uses for side, it can inflate an airbag faster compared with the thing for the conventional side. it is conceivable that.

An example of a first embodiment of a gas generator for an air bag 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 for an air bag according to the present invention. In FIG. 1, an air bag gas generator 1 is equipped with a cylindrical housing 4, a combustion chamber 6 filled with a gas generating agent 5 that generates high-temperature gas by combustion, and a filter material 7 in the housing 4. A filter chamber 8, a first partition member 9 that is partitioned into a gas chamber, and an igniter 10 that ignites and burns the gas generating agent 5 in the combustion chamber 6. The housing 4 has an end 3 that is open. The other end portion 2 has a bottomed cylindrical shape. The outer diameter B of the cylindrical housing 4 is preferably 30 mm or less, and more preferably in the range of 20 mm to 30 mm. The housing 4 is preferably a bottomed cylinder.

The other end 2 of the housing 4 may be any shape such as a rounded shape, a square shape, a bowl shape, or a flat bottom shape. In FIG. 1, it has a bowl shape. Thereby, even if the pressure in the housing rises, deformation can be suppressed. Further, since the other end 2 is closed as described above, only the end 3 needs to be sealed, the number of parts can be reduced, and the sealed portion is only one place at the end 3. Therefore, the safety of the gas generator 1 for an air bag can be improved and the size can be reduced. The housing 4 is made of a metal such as stainless steel or iron.

  A gas discharge hole 11 is provided on the outer periphery of the other end 2 of the housing 4. The gas discharge holes 11 are preferably provided at a position where no propulsive force is generated in the inflator at the time of gas discharge, for example, the cylindrical portion 20 of the filter chamber 8, and a plurality of gas discharge holes 11 may be provided. Instead, they may be provided in a plurality of rows in the axial direction, and when provided in a plurality of rows in the axial direction, they may be provided in a zigzag shape. Preferably, four or eight are provided, and more preferably four are provided every 90 degrees on the same outer periphery or eight are provided every 90 degrees on the outer periphery of two rows in the axial direction. From these gas discharge holes 11, high-temperature and high-pressure gas generated by the combustion of the gas generating agent 5 in the combustion chamber 6 passes through the filter material 7 mounted in the filter chamber 8, and is cooled and filtered. Is done.

The first partition member 9 has an annular flat disk shape, has a hole 18, has a two-chamber structure in which the filter chamber 8 and the combustion chamber 6 (gas generating agent chamber) are separated, and is generated by the combustion heat of the gas generating agent. The filter is prevented from being damaged (melted). The first partition member 9 is made of, for example, stainless steel or iron.
A seal member 16 such as an aluminum tape is affixed to either or both of the position on the inner peripheral side of the housing 4 that covers the gas discharge hole 11 and the position that covers the hole 18 of the first partition member 9. . Thereby, the inside of the housing 4 is sealed. More preferably, the seal member 16 is affixed to the surface on the combustion chamber side of the first partition member 9 and is not affixed to the inner peripheral side of the housing 4. The diameter of the seal member 16 may be 4 mm or more larger than the diameter of the hole 18. The application to the first partition member 9 is simple, and this application can reduce the manufacturing cost of the gas generator for the airbag .

  A holder 12 that holds the igniter 10 is attached to the end 3 of the housing 4, and the holder 12 is held by caulking together with the shaft end 13 of the housing 4 to close the end 3 of the housing 4. is doing.

  In addition, it is preferable that the outer peripheral end surface of the first partition member 9 is hard to be inserted into the inner peripheral surface of the housing 4 by caulking the peripheral surface of the housing 4 in the vicinity of the position where the first partition member 9 is disposed in the direction of reducing the diameter.

  As shown in FIG. 3, the igniter 10 includes an embolus 24 having a pair of mutually insulated electrode pins 22 and 23, and a thin film bridge 25 attached to the embolus 24. A current is supplied to the thin film bridge 25 through the electrode pins 22 and 23, and the thin film bridge 25 is operated to ignite the explosives 26 and 27 loaded in the first tubular body 29.

  The embolus 24 is made of a metal such as stainless steel, aluminum, copper, or iron. Further, the pair of electrode pins 22, 23 extending from the embolus 24 is formed of a metal such as stainless steel, aluminum, copper, iron, etc., like the embolus 24. The electrode pins 22 and 23 are covered with an insulator 31 such as glass or resin in the embolus 24 and insulated from each other. Further, the head portions 35 of these electrode pins 22 and 23 are provided so as to be substantially flush with the header portion 44 of the embolus 24.

  FIG. 4 is an enlarged plan view of the portion where the thin film bridge 25 is embedded in the recess 32 of the embolus 24 as viewed in the direction C. FIG. 5 is a view showing a cross section taken along line A-A ′ in FIG. 4. FIG. 6 is a view showing a cross section taken along line B-B ′ in FIG. 4.

  As shown in FIGS. 4, 5, and 6, the thin film bridge 25 is embedded in a recess 32 formed in the embolus 24, and is substantially flush with the header portion 44 of the embolus 24 and the head portion 35 of the electrode pins 22 and 23. It is installed to become. As shown in FIG. 5, the recess 32 has a groove depth h1 of generally 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 25 is embedded, the step h2 of the electrode pins 22 and 23 with the head 35 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.5 and FIG.6, what is called horizontal attachment which connects using the surrounding surface of the wire 28 in the state which laid the wire 28 can be performed easily. Thus, since the loop height h3 of the wire 28 is usually 1 mm or less, preferably 0.5 mm or less, and more preferably 0.2 mm or less, the wire 28 is subjected to a pressing pressure when loading with an explosive or the like. However, disconnection of the wire 28 can be prevented, and the electrode pins 22 and 23 and the thin film bridge 25 can be reliably connected. The wire 28 is preferably gold or aluminum. This makes it possible to reliably supply current from the electrode pins 22 and 23 to the thin film bridge 25. The wire 28 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 22 and 23 to the thin film bridge 25 more reliably. It becomes.

  As shown in FIGS. 4 and 5, the thin film bridge 25 and the wire 28 that joins the electrode pins 22 and 23 are connected so as to span the surface of the electrode pad 41 of the thin film bridge 25. At this time, as described above, the thin film bridge 25, the header portion 44 of the embolus 24, and the head portions 35 of the electrode pins 22 and 23 are disposed in the recess 32 of the embolus 24 so as to be substantially flush with each other (see FIG. 3), the wire 28 can be bonded to the electrode pad 41 of the thin film bridge 25 by so-called lateral mounting. In addition, by connecting the wire 28 from one electrode pad 41 to the metal portion of the header portion 44 of the embolus 24, it is easy to ground. In addition, the electrode pad 41 wire-bonded to the electrode pins 22 and 23 by the wire 28 is a laminated body 43 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 25 can be any of a heating resistor, a reactive bridge using a reactive substance, a shock bridge, and the like. These are formed on a ceramic substrate such as an Si substrate or Al ₂ O ₃ by a known technique such as a LIGA (Lithographie Galva-noformung, Abfprmung (fine processing technique using X-ray)) process or sputtering. In particular, the reactive bridge is preferable in that it operates stably with small energy.

The reactive thin film bridge 25 shown in the first embodiment of the gas generator for an air bag according to the present invention includes a reactive metal formed on the surface of the substrate 42, for example, as shown in FIGS. , Titanium and the like, and a bridge formed by a laminate 43 in which reactive insulators such as boron are alternately laminated, and an electrode pad 41 formed of a conductive material such as a metal covering the surface. 4, 5, and 6, the electrode pad 41 is located on the stacked body 43.

  Examples of the reactive metal used for the laminate 43 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 25 having such a laminated body 43 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 10 used in the first embodiment of the gas generator for an air bag according to the present invention is manufactured as follows.
As shown in FIG. 3, the igniter 10 used in the first embodiment of the gas generator for an air bag according to the present invention is first loaded with explosives 26 and 27 in the first tubular body 29, After the thin film bridge 25 is installed in the recess 32 shown in FIGS. 3 and 4 formed in the embolus 24, the electrode pins 22 and 23 and the thin film bridge 25 are connected by the wire 28 by wire bonding, and then the first tube body 29 is connected. To fit. At this time, even when the embolus 24 is pressed against the explosive 26 side, as described above, the thin film bridge 25 is embedded in the embolus 24, and the electrode pins 22, 23, there is no risk of disconnection or the like. In this way, after the embolus 24 is fitted to the first tube body 29, the first tube body 29 is inserted into the second tube body 30 and insert-molded into the igniter holder 40. Thereby, it can be suitably used for an igniter for a gas generator used in various safety devices such as an automobile, and is also suitably used for an igniter for a gas generator using an ignition ball.
Note that the present invention is not limited to this manufacturing example. In wire bonding, an ASIC (Application Specific Integrated Circuit) or the like is interposed between any one of the electrode pins 22 and 23 and the thin film bridge 25 to similarly connect them. It is also possible.

As the igniting agents 26 and 27, it is preferable to use zirconium (Zr), tungsten (W), potassium perchlorate (KClO ₄ ) as a component, and fluorine rubber or nitrocellulose as a binder. Is preferred. 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.

  In the igniter 10 configured as described above, when the current is supplied to the electrode pins 22 and 23, the thin film bridge 25 is activated, and the speed is about 1/10 that of the conventional power line. It becomes possible to ignite the explosives 26 and 27 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 25, variations such as ignition delay can be reduced.

  In the igniter 10, since the electrode pins 22 and 23 and the thin film bridge 25 can be reliably connected by wire bonding, for example, between one of the electrode pins 22 and 23 and the thin film bridge 25. It is also possible to connect by wire bonding in the same manner with an ASIC (Application Specific Integrated Circuit) or the like interposed.

And the gas generator 1 for airbags which concerns on the 1st Embodiment of this invention is the filter material 7, the gas generating agent 5, the enhancer agent 14, from the other end part 2 of the housing 4, as shown in FIG. A holder 12 in which the cushion material 15 is filled in order and the igniter 10 is fixed by caulking is inserted. If necessary, a first partition member 9 can be provided between the filter material 7 and the gas generating agent 5.

The filter material 7 is preferably a rounded shape, more preferably a columnar or cylindrical shape, particularly preferably a cylindrical shape, for example, by an aggregate of knitted wire mesh, plain weave wire mesh, or crimp woven metal wire material. The shape is used. In the present embodiment example, the other end portion 2 has a rounded cylindrical shape. The filter material 7 is mounted in contact with the tip of the other end 2 of the housing 4. The filter material 7 is pressed and fixed to the other end 2 of the housing 4 by a first partition member 9 formed of metal or the like that partitions the inside of the housing 4. The first partition member 9 is caulked from the outer peripheral portions of the housing 4 on both sides of the other end portion 2 side and the end portion 3 side with the first partition member 9 interposed therebetween (two locations). The housing 4 is partitioned into a filter chamber 8 and a combustion chamber 6. A space 19 is formed in the center of the filter material 7 in the longitudinal direction so as to cut out the core of the filter material 7. In the gas generator for an air bag of the present invention suitably used for inflating the side air bag or the like, a relatively large amount of a chemical such as the gas generating agent 5 is used. Therefore, the first partition member 9 is preferably used. As a result, the filter chamber 8 and the combustion chamber 6 can be partitioned to prevent the filter from being damaged by the combustion heat of the gas generating agent 5.

  An enhancer agent 14 is filled in the combustion chamber 6. The enhancer agent 14 is protected by the cushion material 15 from being powdered by vibration. The cushion material 15 is formed with a cross-shaped notch for reliably transmitting the power of the flame from the igniter 10 to the enhancer agent 14 without delay. The cushion material 15 is preferably formed using, for example, an elastic material such as silicon rubber or silicon foam formed of ceramic fiber, foamed silicon, or the like. The cushioning material 15 is usually in a disk shape and is preferably formed in one layer.

  The gas generating agent 5 is a non-azide composition, and for example, a composition composed of a fuel, an oxidizing agent, and an additive (binder, slag forming agent, combustion modifier) can be used.

  Examples of the fuel include nitrogen-containing compounds. Examples of the nitrogen-containing compound include one or a mixture of two or more selected from triazole derivatives, tetrazole derivatives, guanidine derivatives, azodicarbonamide derivatives, hydrazine derivatives, urea derivatives, and ammine complexes.

  Specific examples of the triazole derivative include 5-oxo-1,2,4-triazole and aminotriazole. Specific examples of the tetrazole derivatives include tetrazole, 5-aminotetrazole, aminotetrazole nitrate, nitroaminotetrazole, 5,5′-bi-1H-tetrazole, 5,5′-bi-1H-tetrazole diammonium salt, 5 , 5'-azotetrazole diguanidinium salt and the like. Specific examples of the guanidine derivative include guanidine, nitroguanidine, cyanoguanidine, triaminoguanidine nitrate, guanidine nitrate, aminoguanidine nitrate, and guanidine carbonate. Specific examples of the azodicarbonamide derivative include azodicarbonamide and the like. Specific examples of the hydrazine derivative include carbohydrazide, carbohydrazide nitrate complex, oxalic acid dihydrazide, hydrazine nitrate complex, and the like. Examples of the urea derivative include biuret. Examples of the ammine complex include a hexaammine copper complex, a hexaammine cobalt complex, a tetraammine copper complex, and a tetraammine zinc complex.

  Among these nitrogen-containing compounds, one or more selected from tetrazole derivatives and guanidine derivatives are preferable, and nitroguanidine, guanidine nitrate, cyanoguanidine, 5-aminotetrazole, aminoguanidine nitrate, and guanidine carbonate are particularly preferable.

The mixing ratio of these nitrogen-containing compounds in the gas generating agent 5 varies depending on the number of carbon atoms, hydrogen atoms and other oxidized atoms in the molecular formula, but is usually preferably in the range of 20 to 70% by weight, and 30 to 60. A weight percent range is particularly preferred. Moreover, the absolute value of the compounding ratio of the nitrogen-containing compound varies depending on the kind of the oxidizing agent added to the gas generating agent. However, if the absolute value of the compounding ratio of the nitrogen-containing compound is larger than the theoretical amount of complete oxidation, the trace CO concentration in the generated gas increases. On the other hand, the absolute value of the compounding ratio of the nitrogen-containing compound is the theoretical amount of complete oxidation and that. small amount concentration of NO _X generated gas to become less increases. Therefore, the range where the optimum balance between the two is maintained is most preferable.

  As the oxidizing agent, an oxidizing agent selected from at least one of nitrates, nitrites, and perchlorates containing a cation selected from alkali metals, alkaline earth metals, transition metals, and ammonium is preferable. Oxidizing agents other than nitrates, that is, oxidizing agents that are frequently used in the field of airbag inflators such as nitrite and perchlorate can also be used, but the number of oxygen in the nitrite molecule is reduced compared to nitrate, or Nitrate is preferred from the standpoint of reducing the production of fine powder mist that is easily released out of the bag. Examples of the nitrate include sodium nitrate, potassium nitrate, magnesium nitrate, strontium nitrate, phase-stabilized ammonium nitrate, basic copper nitrate, and the like, and strontium nitrate, phase-stabilized ammonium nitrate, and basic copper nitrate are more preferable.

The blending ratio of the oxidizing agent in the gas generating agent 5 is preferably in the range of 30 to 80% by weight, although the absolute value varies depending on the type and amount of the nitrogen-containing compound used, and particularly relates to the above-mentioned CO and NO _x concentrations. The range of 40 to 75% by weight is preferable.

  Any binder can be used as long as it does not significantly adversely affect the combustion behavior of the gas generating agent. Examples of the binder include metal salts of carboxymethyl cellulose, methyl cellulose, hydroxyethyl cellulose, cellulose acetate, cellulose propionate, cellulose acetate butyrate, nitrocellulose, microcrystalline cellulose, guar gum, polyvinyl alcohol, polyacrylamide, starch and other polysaccharides. Examples thereof include organic binders such as derivatives and stearates, inorganic binders such as molybdenum disulfide, synthetic hydroxytalcite, acid clay, talc, bentonite, diatomaceous earth, kaolin, silica, and alumina.

  The blending ratio of the binder is preferably in the range of 0 to 10% by weight in the case of press molding, and is preferably in the range of 2 to 15% by weight in the extrusion molding. As the amount of addition increases, the fracture strength of the molded body increases. However, the number of carbon atoms and hydrogen atoms in the composition increases, the concentration of a trace amount of CO gas that is an incomplete combustion product of carbon atoms increases, and the quality of the generated gas decreases. Moreover, since the combustion of a gas generating agent is inhibited, use by the minimum amount is preferable. In particular, if the amount exceeds 15% by weight, the relative proportion of the oxidant needs to be increased, the relative proportion of the gas generating compound decreases, and it becomes difficult to establish a practical gas generator system.

Moreover, a slag formation agent can be mix | blended as components other than a binder as an additive. The slag forming agent is added in order to facilitate the filtration with the filter material 7 in the gas generator 1 for an air bag by the interaction with the metal oxide generated from the oxidant component in the gas generating agent. .

  Examples of the slag forming agent include naturally occurring clay, synthetic mica, synthetic kaolinite, synthetic smectite and the like mainly composed of aluminosilicates such as silicon nitride, silicon carbide, acid clay, silica, bentonite and kaolin. Among these, artificial clay, talc which is a kind of hydrous magnesium silicate mineral, and the like can be mentioned. Among these, acidic clay or silica is preferable, and acidic clay is particularly preferable. The blending ratio of the slag forming agent is preferably in the range of 0 to 20% by weight, particularly preferably in the range of 2 to 10% by weight. If the amount is too large, the linear combustion rate is lowered and the gas generation efficiency is lowered. If the amount is too small, the slag forming ability cannot be sufficiently exhibited.

  As a preferable combination of the gas generating agent 5, a gas generating agent containing 5-aminotetrazole, strontium nitrate, synthetic hydrotalcite, and silicon nitride, or a gas containing guanidine nitrate, strontium nitrate, basic copper nitrate, and acid clay. Examples include generators.

  Moreover, you may add a combustion regulator as needed. As the combustion modifier, a metal oxide, ferrosilicon, activated carbon, graphite, or a chemical compound such as hexogen, octogen, 5-oxo-3-nitro-1,2,4-triazole can be used. The blending ratio of the combustion modifier is preferably in the range of 0 to 20% by weight, particularly preferably in the range of 2 to 10% by weight. If the amount is too large, the gas generation efficiency is lowered. If the amount is too small, a sufficient combustion rate cannot be obtained.

  The gas generating agent 5 configured as described above is preferably a molded body by press molding or extrusion molding, more preferably an extruded molded body, and the shape thereof is, for example, a pellet shape (generally, one shape of a pharmaceutical product). Tablet shape), a cylindrical shape, a cylindrical shape, a disk shape, or a hollow body shape in which both ends are closed. The cylindrical shape includes a cylindrical shape, and the cylindrical shape includes a single-hole cylindrical shape and a porous cylindrical shape. The hollow body shape with both ends closed includes a cylindrical shape with both ends closed. In addition, the state where both ends of the molded body of the gas generating agent 5 are closed means a state where the holes opened at both ends are closed by two forces from the outside to the inside. The hole may be either completely closed or not fully closed.

  An example of a method for producing the hollow body-shaped gas generating agent 5 with both ends closed will be described. The non-azide composition composed of the above-described nitrogen-containing compound, oxidizing agent, slag forming agent and binder is first mixed by a V-type mixer, a ball mill or the like. Furthermore, it mixes, adding water or a solvent (for example, ethanol), and can obtain the wet mass. Here, the wet state is a state having a certain degree of plasticity, and means a state in which water or a solvent is preferably contained in an amount of 10 to 25% by weight, more preferably 13 to 18% by weight. Then, the outer diameter is preferably 1.4 mm to 4 mm, more preferably 1 with an extruder (for example, a die and an inner hole pin provided at the outlet). It is 0.5 mm to 3.5 mm, and the inner diameter is preferably 0.3 mm to 1.2 mm, more preferably 0.5 mm to 1.2 mm. Thereafter, the hollow cylindrical molded body extruded by the extruder is pressed at regular intervals to obtain a cylindrical molded body closed at both ends. Usually, after pressing the hollow cylindrical molded body at regular intervals, each is cut so as to be folded at each closed depression, and then usually dried in the range of 50 to 60 ° C. for 4 to 10 hours, Usually, a cylindrical gas generating agent having a space inside can be obtained in a state where the end is closed by performing drying in two stages of drying for 10 to 10 hours in a range of 105 to 120 ° C. . The length of the gas generant thus obtained is usually in the range of 1.5 to 8 mm, preferably in the range of 1.5 to 7 mm, more preferably in the range of 2 to 6.5 mm. .

Further, the linear burning rate of the gas generating agent is measured under a constant pressure condition and empirically follows the following Villele equation.
r = aPn
Here, r is a linear burning rate, a is a constant, P is pressure, and n is a pressure index. The pressure index n indicates a slope of a logarithmic plot of the pressure on the X axis with respect to the logarithm of the combustion speed on the Y axis.

The preferred linear burning rate range of the gas generant is 3 to 60 mm / second, more preferably 5 to 35 mm / ^second under 70 kgf / cm ² , and the preferred pressure index range is n = 0.90. Below, more preferably n = 0.75 or less, particularly preferably n = 0.60 or less.

  Moreover, as a method for measuring the linear burning rate, for example, a strand burner method, a small motor method, and a sealed pressure vessel method are generally cited. Specifically, after press-molding to a predetermined size, the burning rate is measured in a high-pressure vessel by a fuse cutting method or the like using a test piece obtained by applying a restrictor on the surface. At this time, the linear combustion rate is measured using the pressure in the high-pressure vessel as a variable, and the pressure index can be obtained from the above-mentioned Villele equation.

Since the gas generating agent is a non-azide-based gas generating agent, the raw materials used are those that are less harmful to the human body. Further, by selecting the fuel component and the oxidant component, the calorific value per mol of generated gas can be suppressed, and the airbag gas generator can be reduced in size and weight.

As the enhancer agent 14, an enhancer agent containing the following composition generally used is used. Examples thereof include a metal powder represented by B / KNO ₃ , a composition containing an oxidizing agent, a composition containing a nitrogen-containing compound / oxidizing agent / metal powder, or a composition similar to the gas generating agent 5 described above. Examples of the nitrogen-containing compound include compounds that can be used as fuel components (aminotetrazole, guanidine nitrate, etc.) of the gas generating agent. Examples of the oxidizing agent include nitrates such as potassium nitrate, sodium nitrate, and strontium nitrate. Examples of the metal powder include boron, magnesium, aluminum, magnalium (magnesium-aluminum alloy), titanium, zirconium, tungsten, and the like. Preferable combinations include those containing 5-aminotetrazole, potassium nitrate and boron, guanidine nitrate, potassium nitrate and boron. And it may contain 0-10% of the binder for shaping | molding as needed.

  In addition, the shape of the enhancer agent 14 is preferably a molded body by press molding or extrusion molding, more preferably an extrusion molded body, and the shape thereof is pellet-shaped (generally corresponding to the shape of a pharmaceutical tablet), columnar shape, cylinder Shape, disk shape, or hollow body shape with both ends closed. Examples of the cylindrical shape include a cylindrical shape, and examples of the cylindrical shape include a single-hole cylindrical shape and a porous cylindrical shape. The hollow body shape with both ends closed includes a cylindrical shape with both ends closed. The outer diameter of the enhancer agent 14 is preferably 1 mm or more. The height of the enhancer is preferably 1 to 5 mm.

The gas generating agent 5 and the enhancer agent 14 are preferably filled in the combustion chamber 6 without being added to the container, separated by a plate-like second partition member 46. Here, the said container usually says the container formed with iron, aluminum, etc. for adding an enhancer etc. Examples of the second partition member 46 include a thin plate, a wire net, an expanded metal, and a punching metal.
The gas generating agent 5 and the enhancer agent 14 are separated and filled by the second partition member 46, so that they do not mix with each other, and the enhancer agent 14 and the enhancer agent 14 differ depending on the filling state of the gas generating agent 5. the gas generating agent 5, because of the close contact through the second partition member 46 (in FIG. 1, a thin plate is used), each other, since there is no resulting distance, the gas for an air bag generator 1 Can stabilize the performance. The thin plate as the second partition member 46 is preferably made of aluminum, iron, SUS or the like, and the thickness thereof is preferably in the range of 0.1 to 0.2 mm. Moreover, it is preferable that the thickness of a metal-mesh and an expanded metal exists in the range of 0.4-1.0 mm.
Further, by making the enhancer agent 14 preferably cylindrical, it is difficult to enter the gap of the gas generating agent 5 when the enhancer agent 14 is filled as compared with a powder or granule. Even after it is attached to the combustion chamber 6, it is possible to prevent them from mixing in the combustion chamber 6. For this reason, the performance of the gas generator for airbags can be made more reliable and stable.

Next, the operation of the air bag gas generator 1 will be described. When the collision sensor detects a collision of the automobile, the airbag gas generator 1 sends a signal to the igniter 10 to ignite it. The flame of the igniter 10 ruptures and opens the cushion material 15, and then blows out into the combustion chamber 6 to ignite the enhancer agent 14, thereby forcibly igniting and burning the gas generating agent 5, thereby generate. The ignition combustion of the gas generating agent 5 is sequentially transferred from the end 3 of the housing 4 to the filter material 7 side.

  When combustion in the combustion chamber 6 progresses and the combustion chamber 6 rises to a predetermined internal pressure, the high temperature gas generated in the combustion chamber 6 passes through the hole 18 and enters the space 19 and passes through the filter material 7. Here, the slag is collected and cooled to become a clean gas. This clean gas is discharged from the gas discharge hole 11.

  As a result, the sufficiently cooled clean gas discharged from the gas discharge hole 11 is directly introduced into the interior of the air belt, the air bag, etc., and instantly expands.

Thus, in the gas generator 1 for airbags which is 1st Embodiment which concerns on this invention, since the thin film bridge 25 is used for the igniter 10, it is quick compared with the conventional electric wire type. It can be ignited reliably in time.

Next, an air bag gas generator 45 according to a second embodiment of the present invention will be described with reference to FIG.
In the second embodiment according to the present invention, the same reference numerals are used for portions common to the airbag gas generator 1 in the first embodiment described above, and detailed description thereof is omitted.

The airbag gas generator 45 according to the present invention differs from the airbag gas generator 1 according to the first embodiment shown in FIG. 1 in that the other end 2 of the housing has a flat bottom shape. The gas discharge holes 11 are arranged in two rows in the axial direction. Even if it does in this way, since the other end part 2 is obstruct | occluded similarly to the gas generator 1 for airbags of this invention, it is only necessary to seal the end part 3, and the number of parts can be reduced. In addition, since the sealing part can be provided only at one end 3, the safety of the gas generator for an air bag can be improved and the size can be reduced.

Further, in the gas generator 45 for an air bag of the present invention, since the gas discharge holes 11 are installed in two rows in the axial direction, the gas generated in the housing 4 is discharged without being concentrated. The damage of the filter material 7 is suppressed. Moreover, the filter material 7 can be used in a wide range, and the filter material 7 can be used efficiently.

The gas generators 1 and 45 for airbags according to the present invention are suitably used as side (side collision) gas generators.

It is sectional drawing of an example of 1st Embodiment of the gas generator for airbags concerning this invention. It is sectional drawing of an example of 2nd Embodiment of the gas generator for airbags concerning this invention. It is sectional drawing of an example of the igniter used for the gas generator for airbags 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.

B outer diameter h1 groove depth h2 level difference h3 loop height 1 gas generator for air bag 2 other end 3 end 4 housing 5 gas generating agent 6 combustion chamber 7 filter material 8 filter chamber 9 first partition member 10 Igniter 11 Gas discharge hole 12 Holder 13 Shaft end 14 Enhancer agent 15 Cushioning material 16 Seal member 19 Space 20 Cylindrical portion 22, 23 Electrode pin 24 Embolization 25 Thin film bridge 26, 27 Explosive 28 Wire-
DESCRIPTION OF SYMBOLS 29 1st pipe body 30 2nd pipe body 31 insulator 32 recessed part 35 head 40 igniter holder 41 electrode pad 42 board | substrate 43 laminated body 44 header part 45 gas generator for airbags 46 2nd partition member

Claims (11)

In the cylindrical housing (4), a combustion chamber (6) filled with a gas generating agent (5) that generates high-temperature gas by combustion, a filter chamber (8) in which a filter material (7) is mounted, An igniter (10) for igniting and burning the gas generating agent (5) in the combustion chamber (6),
The igniter (10) comprises an embolus (24) having at least two or more mutually insulated electrode pins (22, 23), and a thin film bridge (25) attached to the embolus (24), A gas generator (1) for an air bag that supplies current to the thin film bridge (25) through the electrode pins (22, 23) and activates the thin film bridge (25) to ignite explosives (26, 27). There,
The thin film bridge (25) is formed on the embolus (24) so that a step between the head part (35) of the electrode pin (22, 23) and the header part (44) of the embolus (24) is 1 mm or less. The thin film bridge (25) is embedded in the recessed portion (32) provided, and is connected to the electrode pins (22, 23) by lateral wire bonding, and further, the electrode pad (41) of the thin film bridge (25). One side is connected with the metal part of the header part (44) of the said embolus (24) by the wire bonding of the side, The gas generator for airbags characterized by the above-mentioned.   The outer diameter B of the cylindrical housing (4) is 30 mm or less, and the igniter (10) is attached to an end (3) of the housing (4). The gas generator for airbags as described.   The gas generator for an air bag according to claim 2, wherein the housing (4) has a bottomed cylindrical shape in which the end (3) is open and the other end (2) is closed.   The gas generator for an air bag according to any one of claims 1 to 3, wherein a material of a surface of the electrode pad (41) of the thin film bridge (25) is gold, aluminum, nickel, or titanium.   The gas generator for an air bag according to any one of claims 1 to 4, wherein the wire (28) used for the wire bonding is gold or aluminum and has a wire diameter of 10 µm to 500 µm.   The gas generator for an air bag according to any one of claims 1 to 5, wherein a loop height (h3) of the wire (28) of the wire bonding is 1 mm or less.   The first partition member (9) for partitioning the combustion chamber (6) and the filter chamber (8) in which the filter material (7) is mounted. A gas generator for an air bag according to claim 1.   The gas generator for an air bag according to claim 3, wherein the other end (2) of the housing (4) has a bowl shape or a flat bottom shape.   The gas generator for an air bag according to any one of claims 1 to 8, wherein the combustion chamber (6) is filled with an enhancer agent (14). The combustion chamber (6) is directly filled with the gas generating agent (5) and the enhancer agent (14) without putting them in a container, and the gas generating agent (5) and the enhancer agent (14) are secondly added. The gas generator for an air bag according to claim 9 , wherein the gas generator is separated by a partition member (46).   The peripheral surface of the housing (4) is caulked in the direction of reducing the diameter at each of two positions sandwiching the first partition member (9), so that the outer peripheral end surface of the first partition member (9) becomes the housing. The gas generator for an air bag according to claim 7, wherein the inner peripheral surface of (4) is fixed so as to be hard.

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