JP2012040943A - Gas generator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gas generator, which can suitably control the transfer of flame energy by the use of a transfer charge, can be fabricated inexpensively and easily, has a light weight and dose not cause fluctuations in output characteristics.SOLUTION: The gas generator 1A includes: a short and cylindrical housing, in which the both ends consisting of an initiator shell 10 and a closure shell 20 are closed; an igniter 30 attached to the initiator shell 10; and an enhancer cup 40 made of a single member in a cylindrical shape having a bottom, in which the transfer charge 34 to be ignited by the igniter 30 is stored. The enhancer cup 40 has, on a side wall part 42: a thin weak part 42a which is ruptured or melted by combustion of the transfer charge 34 accompanying the operation of the igniter 30; and thick non-weak parts 42b, 42c which remain without being ruptured or melted even by the combustion of the transfer charge 34 accompanying the operation of the igniter 30; wherein the weak part 42a is located so as to be put between the non-weak parts 42b, 42c along the axial direction of the enhancer cup 40.

Description

  The present invention relates to a gas generator incorporated in an occupant protection device, and more particularly to a gas generator incorporated in an airbag device mounted on a steering wheel or the like of an automobile.

  2. Description of the Related Art Conventionally, airbag devices, which are occupant protection devices, have been widely used from the viewpoint of protecting occupants such as automobiles. The airbag device is equipped for the purpose of protecting the occupant from the impact generated when the vehicle or the like collides. The airbag is inflated and deployed instantaneously when the vehicle or the like collides, so that the airbag becomes a cushion of the occupant. It is to catch the body. The gas generator is incorporated in the airbag device, and igniters (squibs) are ignited by energization from the control unit (actuator) in the event of a vehicle collision, etc., and the gas generating agent is combusted by the flame generated in the igniter. Is a device that instantaneously generates the working gas and thereby inflates and deploys the airbag. Note that the airbag device is mounted on, for example, an automobile steering wheel or an instrument panel.

  There are various types of gas generators, and there is a so-called disk-type gas generator as a gas generator suitably used for a driver side airbag device equipped on a steering wheel or the like. A disk-type gas generator has a short cylindrical housing closed at both ends in the axial direction, a gas outlet is provided on the peripheral wall of the housing, and a gas generating agent, an igniter, and the like are accommodated inside the housing. It will be.

  In this disk type gas generator, combustion is accelerated between the combustion chamber containing the gas generating agent and the igniter so that the gas generating agent is surely ignited by the flame generated in the igniter. It is common that an explosive (enhancer) as an agent is arranged. Usually, the charge transfer agent is contained in a transfer chamber provided inside a cup-shaped member called an enhancer cup, and the enhancer cup is placed in the combustion chamber so that the transfer chamber faces the ignition part (squib cup) of the igniter. It is arranged in a protruding state. As literatures that disclose such a gas generator, there are, for example, Japanese Patent Laid-Open No. 2002-370607 (Patent Document 1) and Japanese Patent Laid-Open No. 2008-183939 (Patent Document 2).

  Here, in the gas generator, it is important that the combustion of the gas generating agent is designed to exhibit desired combustion characteristics so that a desired gas output suitable for inflation and deployment of the airbag can be obtained. is there. For this purpose, it is important that flame energy generated in the igniter is transmitted to the gas generating agent with good controllability, and in particular, it is important to control the transmission of flame energy by the transfer agent.

  For this reason, in the gas generator disclosed in Patent Document 1 described above, an enhancer holder having a high mechanical strength such as a stainless alloy is used, and an opening of a predetermined size is provided at a predetermined position of the enhancer holder. Thus, the transmission of flame energy due to the combustion of the explosive charge is controlled.

  However, when an enhancer holder having an opening as described above is used, in order to prevent the transfer agent from moving to the combustion chamber or the gas generating agent from moving to the transfer chamber due to vibration or the like, It is necessary to close the opening with a member. Normally, an aluminum foil with an adhesive member applied on one side is used as a sealing member that closes the opening. However, the aluminum foil is very thin and difficult to handle, and the manufacturing process becomes complicated. is there. In addition, in recent years, weight reduction of automobiles has become an increasingly important issue. However, when an enhancer holder with high mechanical strength such as a stainless steel alloy is used as described above, the weight of the enhancer holder increases. There is also a problem that the weight of the entire gas generator increases. Further, when the enhancer holder as disclosed in Patent Document 1 described above is used, at least a part of the top wall portion of the enhancer holder remains even when the transfer charge is ignited. As a result, the transmission of flame energy is hindered, causing a delay in ignition of the gas generating agent, resulting in a delay in gas output during operation of the gas generator. Furthermore, when adopting a form in which holes are partially provided along the circumferential direction and the axial direction as in the conventional enhancer holder described in FIG. Because the flame energy is transmitted in a straight line from the hole, the flame energy is concentrated and transmitted to a part of the gas generating agent, so the combustion characteristics are greatly affected by the state of the gas generating agent that receives the flame energy. There may be a problem that the gas output changes and as a result, the gas output varies greatly.

  Therefore, it has been studied to use an enhancer cup that has a low mechanical strength and is configured to burst or melt with the ignition of the transfer charge. When such an enhancer cup is used, it is not necessary to provide an opening in the enhancer cup in advance, and the above-described opening closing operation is not required, so that the manufacturing process can be greatly simplified. In addition, if an enhancer cup with low mechanical strength can be used, the enhancer cup itself can be reduced in weight, and not only the weight of the gas generator can be reduced, but also the amount of material used. From the viewpoints of cost reduction and resource protection accompanying the reduction of the cost, it is very suitable.

  However, if the entire enhancer cup is made weak so that the pressure in the transfer chamber is increased by the ignition of the transfer charge and the enhancer cup bursts or melts due to its heat, The generated flame rapidly flows into the combustion chamber and is transmitted to the gas generating agent. For this reason, the gas generating agent burns rapidly, and it becomes very difficult to adjust the gas output such as maintaining the gas output for a predetermined time. Thus, when making the whole enhancer cup weak, the subject that control of the transmission of the flame energy by a gunpowder becomes very difficult with the fall of the mechanical strength exists.

  Therefore, in the gas generator disclosed in Patent Document 2, by providing a partition wall in the combustion chamber so as to surround the enhancer cup, the spread of the ignited gas generant is restricted by the partition wall. This intentionally delays the progress of the combustion of the gas generating agent accommodated in the combustion chamber, thereby making it possible to adjust the combustion characteristics of the gas generating agent.

JP 2002-370607 A JP 2008-183939 A

  However, in the case of the gas generator disclosed in Patent Document 2, it is necessary to separately provide the gas generator with a partition wall for restricting the spread of the gas generating agent, and the partition wall is provided. There was a problem that the weight of the gas generator increased by the amount. Further, when the partition portion is provided in the combustion chamber, the partition portion becomes an obstacle, and there is a problem in that the gas generating agent is quickly and uniformly filled in the combustion chamber in the gas generating agent filling step. there were. Furthermore, when a partition is provided in the combustion chamber, unintentional deformation may occur in the partition due to the pressure generated by the combustion of the gas generating agent, resulting in variations in the output characteristics of the gas generator. There was also a problem. Therefore, the gas generator disclosed in Patent Document 2 still has room for improvement from the viewpoints of weight reduction, ease of manufacturing work, and controllability of combustion characteristics.

  Accordingly, the present invention has been made to solve the above-described problems, and the transmission of flame energy by the transfer agent is suitably controllable, and can be manufactured at low cost and easily with a variation in output characteristics. It aims at providing the gas generator which does not produce.

  The gas generator based on this invention is provided with the housing, the igniter, and the cup-shaped member. The housing is composed of a short cylindrical member composed of a top plate portion and a bottom plate portion that closes the end portion in the axial direction, and a peripheral wall portion provided with a gas outlet, and combustion in which a gas generating agent is accommodated Contains chambers inside. The igniter includes an igniter that is attached to the bottom plate and contains an igniting agent that ignites during operation. The cup-shaped member includes a heat transfer chamber in which a charge transfer material is accommodated, and has a bottomed cylindrical shape disposed so as to protrude toward the combustion chamber so that the heat transfer chamber faces the ignition part. It consists of a single member. The cup-shaped member includes a thin fragile portion that bursts or melts due to combustion of the explosive agent accompanying the operation of the igniter, and a side wall portion that divides the transfer chamber and the combustion chamber. And a thick non-fragile portion that remains without being ruptured and melted by the combustion of the above-mentioned transfer charge. The fragile portion is provided in an annular shape along the circumferential direction of the cup-shaped member at an intermediate position of the side wall portion in the axial direction of the cup-shaped member, and along the axial direction of the cup-shaped member by the non-fragile portion. It is sandwiched and located.

  In the gas generator based on the said invention, it is preferable that the said weak part is comprised by the groove | channel provided in the outer peripheral surface of the said side wall part of the said cup-shaped member.

  In the gas generator according to the present invention, the intermediate position where the fragile portion is provided is positioned closer to the top plate portion than the ignition portion along the axial direction of the cup-shaped member. The cup-shaped member is preferably configured.

  In the gas generator according to the present invention, the cup-shaped member is preferably a press-formed product made of aluminum or aluminum alloy.

  ADVANTAGE OF THE INVENTION According to this invention, it can be set as the light-weight gas generator which does not produce dispersion | variation in the light weight which can control suitably the transmission of the flame energy by a transfer powder, can be manufactured cheaply and easily.

It is a schematic cross section of a gas generator in an embodiment of the present invention. It is a schematic cross section which shows the behavior of the cup-shaped member at the time of the action | operation of the gas generator in embodiment of this invention. It is a schematic cross section of the gas generator which concerns on the modification of embodiment of this invention. It is a schematic cross section which shows the behavior of the cup-shaped member at the time of the action | operation of the gas generator which concerns on the modification of embodiment of this invention. It is a graph which shows the result of having performed the performance test of the gas generator which concerns on an Example and a comparative example. It is a graph which shows the result of having performed the performance test of the gas generator which concerns on an Example and a comparative example. It is a schematic cross section of the gas generator concerning a comparative example.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The following embodiment shows a case where the present invention is applied to a so-called disk-type gas generator incorporated in an airbag apparatus mounted on a steering wheel of an automobile.

  FIG. 1 is a schematic cross-sectional view of a gas generator according to an embodiment of the present invention. First, with reference to FIG. 1, the structure of the gas generator in this Embodiment is demonstrated.

  As shown in FIG. 1, the gas generator 1A according to the present embodiment has a short cylindrical housing closed at both ends in the axial direction, and various components are accommodated inside the housing. Yes. The housing is formed by combining an initiator shell 10 and a closure shell 20 each formed in a bottomed cylindrical shape. More specifically, the initiator shell 10 has a bottom plate portion 11 and a peripheral wall portion 12, and the closure shell 20 has a top plate portion 21 and a peripheral wall portion 22. By being combined so that the open ends of the closure shell 20 face each other, a space for accommodating various components is formed therein.

  Each of the initiator shell 10 and the closure shell 20 is made of a metal member such as stainless steel, steel, an aluminum alloy, or a stainless alloy. More specifically, the initiator shell 10 and the closure shell 20 are each forged, drawn, or pressed from a single plate or piece of block-like metal member using a die or the like corresponding to each part. By combining processing and the like, molding is performed by repeated pressurization and flow. For joining the initiator shell 10 and the closure shell 20, electron beam welding, laser welding, friction welding, or the like is preferably used.

  A holding portion 13 is formed at a substantially central portion of the bottom plate portion 11 of the initiator shell 10. The holding unit 13 is a part for holding the igniter 30 when the igniter 30 is inserted. Specifically, the igniter 30 is attached to the holding unit 13 from the inside of the initiator shell 10 so that the terminal pin 32 of the igniter 30 is inserted into the opening provided in the holding unit 13. The igniter 30 is caulked and fixed to the holding portion 13 of the initiator shell 10 by caulking the caulking portion 14 a provided at the tip toward the igniter 30 side. A harness connector (not shown) for connecting the igniter 30 and the control unit is connected to the terminal pin 32 disposed so as to be exposed to the outside of the housing.

  The igniter 30 is an ignition device for generating a flame, and includes an ignition unit 31 and the terminal pin 32 described above. The ignition unit 31 includes therein an igniting agent that ignites during operation and a resistor for burning the igniting agent. The terminal pin 32 is connected to the ignition unit 31 in order to ignite the igniting agent.

  More specifically, the igniter 30 includes a base portion through which a pair of terminal pins 32 are inserted and held, and a squib cup attached to the base portion, and the terminal pins 32 inserted into the squib cup. A resistor (bridge wire) is attached so as to connect the tips of the squib cups, and an igniting agent is filled in the squib cup so as to surround the resistor or in contact with the resistor. Nichrome wire or the like is generally used as the resistor, and ZPP (zirconium / potassium perchlorate), ZWPP (zirconium / tungsten / potassium perchlorate), lead tricinate, or the like is generally used as the igniting agent. The squib cup is generally made of metal or plastic.

  When a collision is detected, a predetermined amount of current flows through the resistor via the terminal pin 32. When a predetermined amount of current flows through the resistor, Joule heat is generated in the resistor, and the ignition agent starts burning. The high temperature flame generated by the combustion ruptures the squib cup containing the igniting agent. The time from when the current flows through the resistor until the igniter 30 is activated is generally 2 milliseconds or less when a nichrome wire is used as the resistor.

  A seal member 33 is interposed between the igniter 30 and the holding unit 13. The seal member 33 is for hermetically sealing a gap generated between the igniter 30 and the holding unit 13 to hermetically seal a transfer chamber 44 described later, and the igniter 30 is caulked to the holding unit 13. When it is fixed, it is inserted into the gap. The seal member 33 is preferably made of a material having sufficient heat resistance and durability. For example, an O-ring made of EPDM resin, which is a kind of ethylene propylene rubber, is preferably used. In addition, if the liquid sealing agent is separately applied to the portion where the sealing member 33 is interposed, the sealing performance of the fire transfer chamber 44 can be further improved.

  An enhancer cup 40 as a bottomed cylindrical cup-shaped member is fixed to the holding portion 13 of the initiator shell 10 so as to cover the igniter 30. The enhancer cup 40 has a top wall portion 41, a side wall portion 42, and a flange portion 43, and includes a fire transfer chamber 44 in which a charge transfer agent 34 is accommodated. The enhancer cup 40 is a member for partitioning the fire transfer chamber 44 and a combustion chamber 50 described later, and is a press-formed product formed by pressing a single plate-shaped or one-piece block-shaped metal member. Consists of.

  The enhancer cup 40 is composed of a single member (that is, one part), and is fixed to the holding unit 13 so that the heat transfer chamber 44 provided in the enhancer cup 40 faces the ignition unit 31. More specifically, the enhancer cup 40 is fixed to the holding portion 13 by caulking the flange portion 43 of the enhancer cup 40 by the caulking portion 14 b provided in the holding portion 13.

  The enhancer cup 40 has no opening in either the top wall portion 41 or the side wall portion 42, and the enhancer cup 40 is fixed to the holding portion 13 of the initiator shell 10 and the transmission provided in the enhancer cup 40. The fire chamber 44 is completely sealed. The enhancer cup 40 ruptures or melts partly with the increase in pressure in the transfer chamber 44 and the conduction of generated heat when the transfer powder 34 is ignited by the operation of the igniter 30. The mechanical strength is lower than that of a conventional stainless steel enhancer cup. As the material of the enhancer cup 40, metal is preferably used, and aluminum, aluminum alloy, and the like are particularly preferably used from the viewpoints of formability and weight reduction during press working.

  The side wall portion 42 of the enhancer cup 40 is provided with a thin fragile portion 42a and a pair of thick non-fragile portions 42b and 42c. More specifically, the fragile portion 42a is a thin portion of the enhancer cup 40 formed by providing an annular groove on the outer peripheral surface of the side wall portion 42 of the enhancer cup 40 so as to extend along the circumferential direction. The non-fragile portions 42b and 42c are configured by a thick portion of the enhancer cup 40 in which the annular groove is not provided.

  The thin fragile portion 42a is provided at an intermediate position of the side wall portion 42 in the axial direction of the enhancer cup 40 (a position where the height is h shown in the figure when the upper surface of the top wall portion 41 is used as a reference). Yes. In contrast, one non-fragile portion 42b is provided so as to reach from the midway position to the axial end of the side wall portion 42 of the enhancer cup 40 on the flange 43 side, and the other non-fragile portion 42c The intermediate wall is provided so as to reach the axial end on the top wall 41 side of the side wall 42 of the enhancer cup 40 from the midway position. As described above, the thin fragile portion 42 a is positioned between the pair of thick non-fragile portions 42 b and 42 c along the axial direction of the enhancer cup 40. In the gas generator 1A in the present embodiment, the position where the fragile portion 42a is provided is a position closer to the top wall portion 41 in the axial direction of the enhancer cup 40.

  Here, the fragile portion 42a is configured to be ruptured or melted by the combustion of the charge transfer 34 accompanying the operation of the igniter 30 by being formed thinner than the non-fragile portions 42b and 42c. Yes. On the other hand, the non-fragile portions 42b and 42c are formed so as to be thicker than the fragile portion 42a, so that the non-fragile portions 42b and 42c remain without being ruptured and melted by the combustion of the charge transfer agent 34 accompanying the operation of the igniter 30. It is configured.

  In addition, although the thickness t2 of the weak part 42a mentioned above and the thickness t3, t4 of the non-fragile parts 42b and 42c are suitably adjusted based on the kind, filling amount, etc. of the explosive 34 used, the example Is shown below. For example, when the enhancer cup 40 is made of aluminum or aluminum alloy, the thickness t2 of the fragile portion 42a is 1.0 mm or less, preferably 0.5 mm or less, and more preferably 0.3 mm or less. It is said. On the other hand, when the enhancer cup 40 is made of aluminum or aluminum alloy, the thicknesses t3 and t4 of the non-fragile portions 42b and 42c are 0.5 mm or more on condition that the thickness t2 is smaller than the thickness t2 of the fragile portion 42a. It is set to 1.2 mm or less, preferably 0.5 mm to 1.0 mm, and more preferably 0.6 mm to 0.9 mm. The thickness t1 of the top wall portion 41 of the enhancer cup 40 is not particularly limited. However, in consideration of the formability during press molding, the thicknesses t3 and t4 of the non-fragile portions 42b and 42c It is preferable that the degree is equivalent.

The explosive charge 34 filled in the heat transfer chamber 44 is ignited by a flame generated by the operation of the igniter 30 and burns to generate hot particles. The charge transfer agent 34 must be capable of reliably starting the combustion of a gas generating agent 51 to be described later. Generally, from the metal powder / oxidant represented by B / KNO ₃ or the like. The composition etc. which become are used. As the explosive charge 34, a powdery one, a one formed into a predetermined shape by a binder, or the like is used. Examples of the shape of the charge transfer agent formed by the binder include various shapes such as a granular shape, a columnar shape, a sheet shape, a spherical shape, a single-hole cylindrical shape, a porous cylindrical shape, and a tablet shape.

  A combustion chamber 50 in which the gas generating agent 51 is accommodated is located in a space surrounding the portion where the above-described enhancer cup 40 is disposed in the space inside the housing formed of the initiator shell 10 and the closure shell 20. More specifically, the above-described enhancer cup 40 is disposed so as to protrude into a combustion chamber 50 formed inside the housing, and a portion and a side wall facing the outer surface of the top wall portion 41 of the enhancer cup 40. A space provided in a portion facing the outer surface of the portion 42 is configured as a combustion chamber 50. Here, in the gas generator 1 </ b> A in the present embodiment, the gas generating agent 51 is accommodated only in the space of the combustion chamber 50 that faces the outer surface of the side wall portion 42 of the enhancer cup 40.

  A filter 55 is disposed in the space surrounding the combustion chamber 50 along the inner periphery of the housing. The filter 55 has a cylindrical shape, and the center axis thereof is disposed so as to substantially coincide with the axial direction of the housing.

  The gas generating agent 51 is ignited by the heat particles generated by the combustion of the charge transfer agent 34 ignited by the igniter 30, and generates gas by burning. The gas generating agent 51 is preferably a non-azide gas generating agent, and is generally formed as a molded body containing a fuel, an oxidant, and an additive. As the fuel, for example, a triazole derivative, a tetrazole derivative, a guanidine derivative, an azodicarbonamide derivative, a hydrazine derivative, or a combination thereof is used. Specifically, for example, nitroguanidine, guanidine nitrate, cyanoguanidine, 5-aminotetrazole and the like are preferably used. In addition, as the oxidizing agent, for example, nitrate containing a cation selected from alkali metals, alkaline earth metals, transition metals, and ammonia is used. As the nitrate, for example, sodium nitrate, potassium nitrate and the like are preferably used. In addition, examples of the additive include a binder, a slag forming agent, and a combustion adjusting agent. As the binder, for example, an organic binder such as a metal salt of carboxymethyl cellulose or a stearate, or an inorganic binder such as synthetic hydroxytalcite or acidic clay can be suitably used. As the slag forming agent, silicon nitride, silica, acid clay, etc. can be suitably used. Moreover, as a combustion regulator, a metal oxide, ferrosilicon, activated carbon, graphite, etc. can be used suitably.

  The shape of the molded body of the gas generating agent 51 includes various shapes such as a granular shape, a pellet shape, a granular shape such as a cylindrical shape, and a disk shape. In addition, in the cylindrical shape, a porous (for example, a single-hole cylindrical shape or a porous cylindrical shape) having a hole in the molded body is also used. These shapes are preferably selected as appropriate according to the specifications of the airbag apparatus in which the gas generator 1A is incorporated. For example, a shape in which the gas generation rate changes with time during the combustion of the gas generating agent 51 is selected. It is preferable to select an optimal shape according to the specifications. In addition to the shape of the gas generating agent 51, it is preferable to appropriately select the size and filling amount of the molded body in consideration of the linear combustion rate, the pressure index, etc. of the gas generating agent 51.

  The filter 55 is, for example, one obtained by winding and sintering a metal wire such as stainless steel or steel, one obtained by pressing a net material knitted with a metal wire, or by winding a perforated metal plate. Things are used. Here, as the net material, specifically, a knit metal mesh, a plain weave metal mesh, an assembly of crimped metal wires, or the like is used. In addition, as a perforated metal plate, for example, expanded metal that has been cut into a zigzag pattern on the metal plate and expanded to form a hole and processed into a mesh shape, or a hole is formed in the metal plate and at that time A hook metal or the like obtained by flattening the burr generated at the periphery of the hole is used. In this case, the size and shape of the hole to be formed can be appropriately changed as necessary, and holes of different sizes and shapes may be included on the same metal plate. In addition, as a metal plate, a steel plate (mild steel), a stainless steel plate, for example can be used suitably, and nonferrous metal plates, such as aluminum, copper, titanium, nickel, or these alloys, can also be utilized.

  When the working gas generated in the combustion chamber 50 passes through the filter 55, the filter 55 functions as a cooling means that cools the working gas by taking high-temperature heat of the working gas, and in the working gas. It also functions as a removing means for removing the residue (slag) and the like contained in. Therefore, in order to sufficiently cool the working gas and prevent the residue from being discharged to the outside, it is necessary to ensure that the working gas generated in the combustion chamber 50 passes through the filter 55. is there.

  A plurality of gas outlets 23 are provided on the peripheral wall 22 of the portion of the closure shell 20 that faces the filter 55. The gas outlet 23 is for leading the working gas that has passed through the filter 55 to the outside of the housing. A seal member 24 is affixed to the main surface located on the filter 55 side of the peripheral wall portion 22 of the closure shell 20 so as to close the gas ejection port 23. As the sealing member 24, an aluminum foil or the like having an adhesive member applied on one side is used. Thereby, the airtightness of the combustion chamber 50 is ensured.

  A closure shell side holding member 52 for fixing the upper end of the filter 55 to the housing is disposed at the end of the closure shell 20 on the top plate portion 21 side in the space inside the housing. The closure shell side holding member 52 has a portion that comes into contact with the top plate portion 21 of the closure shell 20 and a portion that comes into contact with the inner peripheral surface of the upper end portion of the filter 55. A cushion member 53 is disposed inside the closure shell side holding member 52 so as to come into contact with the gas generating agent 51 accommodated in the combustion chamber 50. The cushion material 53 is provided for the purpose of preventing the gas generating agent 51 made of a molded body from being pulverized by vibration or the like, and a ceramic fiber molded body, foamed silicon, or the like is preferably used.

  On the other hand, an initiator shell side holding member 54 for fixing the lower end of the filter 55 to the housing is disposed at the end of the initiator shell 10 on the bottom plate portion 11 side in the space inside the housing. The initiator shell side holding member 54 has a portion that contacts the inner bottom surface of the bottom plate portion 11 of the initiator shell 10 and a portion that contacts the inner peripheral surface of the lower end portion of the filter 55.

  The closure shell side holding member 52 and the initiator shell side holding member 54 are formed by, for example, pressing a single metal plate-like member, and preferably steel plates such as ordinary steel and special steel. (For example, a cold rolled steel plate (SPCC), a stainless steel plate (SUS304), etc.) is used. Since the closure shell side holding member 52 and the initiator shell side holding member 54 are formed by bending a part of the metal plate-like member as described above, the closure shell side holding member 52 and the initiator shell side holding member 54 are held. Each member 54 has appropriate elasticity. Therefore, the closure shell side holding member 52 and the initiator shell side holding member 54 are in appropriate pressure contact with the inner peripheral surface of the filter 55, whereby the filter 55 is held and fixed by the housing. . Each of the closure shell side holding member 52 and the initiator shell side holding member 54 includes a gap between the upper end of the filter 55 and the top plate portion 21 of the closure shell 20 and the lower end of the filter 55 and the bottom plate portion 11 of the initiator shell 10. It also functions to prevent the outflow of gas from the gap between the two.

  Next, with reference to FIG. 1, the procedure for assembling the gas generator 1A in the present embodiment will be described.

  First, the igniter 30 is caulked and fixed by attaching the seal member 33 to the holding portion 13 of the initiator shell 10. Then, the enhancer cup 40 in which the transfer charge 34 is accommodated is caulked and fixed to the holding portion 13 of the initiator shell 10. Next, the initiator shell side holding member 54 and the filter 55 are inserted and arranged toward the inner bottom surface of the initiator shell 10.

  Then, the gas generating agent 51 is filled inside the filter 55, and the closure shell side holding member 52 having the cushion material 53 interposed is inserted into the upper end portion of the filter 55. Thereafter, the closure shell 20 whose gas outlet 23 is closed by the seal member 24 is placed on the initiator shell 10, and the initiator shell 10 and the closure shell 20 are welded together. Thus, the assembly of the gas generator 1A having the structure shown in FIG. 1 is completed.

  Here, in the gas generator 1A according to the present embodiment, since the enhancer cup 40 is not provided with an opening, the process of filling the transfer chamber 44 provided in the enhancer cup 40 with the transfer agent 34 is extremely necessary. Easy to do. This is because the enhancer cup 40 itself is composed of a fragile member having low mechanical strength so that a part of the enhancer cup 40 is ruptured or melted during operation of the gas generator 1A. That is, the operation | work which obstruct | occluded the opening provided in the enhancer cup in order to fill with a charge is unnecessary when using the enhancer holder which has an opening as disclosed by the patent document 1 mentioned above. Therefore, the manufacturing process can be greatly simplified.

  FIG. 2 is a schematic cross-sectional view showing the behavior of the cup-shaped member during operation of the gas generator in the present embodiment. Next, with reference to this FIG. 2, the operation | movement at the time of the action | operation of the gas generator in this Embodiment is demonstrated.

  When a vehicle on which the gas generator 1A according to the present embodiment is mounted collides, the collision is detected by a collision detection unit provided separately in the vehicle, and the igniter 30 is operated based on this. The charge transfer agent 34 accommodated in the transfer chamber 44 is ignited and burned by the flame generated by the operation of the igniter 30, and generates a large amount of heat particles. When the pressure in the enhancer cup 40 increases due to the combustion of the charge transfer agent 34, the weakened portion 42 a of the enhancer cup 40 is ruptured or melted by the pressure or heat, and the above-described hot particles flow into the combustion chamber 50. At this time, the non-fragile portions 42b and 42c of the enhancer cup 40 will remain without being ruptured and melted, and the end portion on the top wall 41 side of the enhancer cup 40 including the non-fragile portion 42c is As the internal pressure of the heat transfer chamber 44 increases, the air is blown toward the closure shell 21 side.

  The gas generating agent 51 accommodated in the combustion chamber 50 is ignited and burned by the flowing heat particles, and a large amount of working gas is generated. The working gas generated in the combustion chamber 50 passes through the filter 55. At that time, heat is taken away by the filter 55 and cooled, and the residue contained in the working gas is removed by the filter 55. The working gas after passing through the filter 55 flows into the outer peripheral edge of the housing, and then is ejected from the gas ejection port 23 provided in the peripheral wall portion 22 of the closure shell 20 to the outside of the housing. The jetted gas is introduced into an airbag provided adjacent to the gas generator 1A, and the airbag is inflated and deployed.

  Below, with reference to FIG. 1 and FIG. 2, when it is set as the gas generator 1A in this Embodiment, the mechanism in which transmission of the flame energy by a transfer agent becomes controllable suitably is demonstrated.

  As shown in FIG. 1, in the gas generator 1 </ b> A according to the present embodiment, the weakened portion is obtained by making the thickness t <b> 2 at the midway position of the side wall portion 42 in the axial direction of the enhancer cup 40 thinner than other portions. The non-fragile portions 42b and 42c are configured by forming a thickness 42a and making the remaining portions t3 and t4 of the side wall portion 42 of the enhancer cup 40 thicker than the thickness t2 of the weakened portion 42a. Here, the position at which the fragile portion 42 a is provided is not particularly limited, but is closer to the top plate portion 21 side of the closure shell 20 than the ignition portion 31 of the igniter 30 along the axial direction of the enhancer cup 40. It is preferable. That is, the height h of the intermediate position when the upper surface of the top wall portion 41 of the enhancer cup 40 is used as a reference is smaller than the height H of the upper surface of the ignition unit 31 when the upper surface is used as a reference. (That is, satisfying the condition of h <H).

  With this configuration, as shown in FIG. 2, only the weakened portion 42 a of the enhancer cup 40 is ruptured or melted in the state where the transfer charge 34 is burned by the operation of the igniter 30, and the non-fragile portions 42 b and 42 c. Of the enhancer cup 40 including the non-fragile portion 42c, the end of the enhancer cup 40 on the side of the closure shell 21 as the internal pressure rises. It will be blown toward and move. As a result, the flame flowing into the combustion chamber 50 is throttled by the gap generated between the non-fragile portion 42b and the moved non-fragile portion 42c, and all of the gas generating agent 51 adjacent to the enhancer cup 40 is obtained. Are not ignited simultaneously at the same time, and the spread of the gas generating agent 51 proceeds radially around the gap. Note that the spread of the gas generating agent 51 is schematically represented by broken-line arrows in FIG.

  Here, the axial size d (see FIG. 2) of the gap generated between the non-fragile portion 42b and the moved non-fragile portion 42c is the upper surface of the top wall portion 41 of the enhancer cup 40 during non-operation. Depending on the distance D (see FIG. 1) between the inner surface of the closure shell 21 (more specifically, the lower surface of the closure shell-side holding member 52) and the axial size w (see FIG. 1) of the fragile portion 42a. Determined. Therefore, the enhancer cup 40 is provided with the fragile portion 42a and the non-fragile portions 42b and 42c, the position and size of the fragile portion 42a and the non-fragile portions 42b and 42c, and the top wall portion 41 and the closure shell of the enhancer cup 40. By appropriately adjusting the distance between the inner surface of the gas generator 21 and the like in advance, the gas generating agent 51 can be prevented from rapidly burning and the progress of the combustion can be intentionally delayed. It is very easy to optimize the adjustment of the gas output according to the specification, such as sustaining over a period of time.

  Further, when all the side wall portions 42 of the enhancer cup 40 are configured to be thin, an impact when the enhancer cup 40 is ruptured or melted due to combustion of the transfer powder 34 may be applied to the filter 55 and the filter 55 may be damaged. However, by providing the non-fragile portions 42b and 42c on the side wall portion 42 of the enhancer cup 40 as in the gas generator 1A in the present embodiment, the impact applied to the filter 55 is mitigated and the damage is not caused. The effect which is prevented by this is also obtained.

  In addition, by adopting the above configuration, the end portion near the top wall portion 41 of the enhancer cup 40 including the non-fragile portion 42c due to the fragile portion 42a bursting or melting when the transfer charge 34 is ignited becomes a non-fragile portion. Since it is detached from 42b and moves toward the top plate portion 21 side of the housing, there is no delay in gas output that occurs when the enhancer holder as disclosed in Patent Document 1 described above is used. . Furthermore, as shown in FIG. 1, by providing the annular weak portion 42a on the side wall 42 of the enhancer cup 40, the side wall 42 of the enhancer cup 40 is continuously provided along the circumferential direction when the transfer charge 34 is ignited. Since the gap is formed, the flame energy of the charge transfer agent 34 is transmitted to the gas generating agent 51 through the annular gap. Therefore, it is possible to secure a sufficiently large flame energy transmission area, and to effectively suppress variations in gas output.

  Further, by adopting the above configuration, it is not necessary to provide the partition wall as disclosed in Patent Document 2 in the combustion chamber, so that it is possible to prevent the output characteristics from varying.

  As described above, by using the gas generator 1A in the present embodiment, it is possible to suitably control the transmission of the flame energy by the charge transfer agent, and it is possible to produce light weight and output characteristics that can be easily and inexpensively manufactured. It is possible to provide a gas generator in which no variation occurs.

  In this Embodiment demonstrated above, the case where the weak part 42a was arrange | positioned in the position near the top wall part 41 of the enhancer cup 40 was illustrated. However, as described above, by appropriately adjusting the position where the fragile portion 42a is provided and the axial size of the fragile portion 42a, the progress of the combustion of the gas generating agent 51 is intentionally delayed. It is possible to adjust appropriately. In the following, a case where the position where the fragile portion is provided is set to a position different from the above-described position and the size of the fragile portion in the axial direction is set as a different size will be exemplified as a modification of the present embodiment. . FIG. 3 is a schematic cross-sectional view showing a gas generator according to a modification of the present embodiment. FIG. 4 shows the behavior of the cup-shaped member during operation of the gas generator according to the modification of the present embodiment. It is a schematic cross section.

  In the gas generator 1B according to this modification shown in FIG. 3, the position where the weakened portion 42a is provided is closer to the substantially central portion in the axial direction of the enhancer cup 40 than the gas generator 1A in the present embodiment described above. While arrange | positioning in a position, the magnitude | size in the axial direction of the weak part 42a is made larger. In the case of such a configuration, as shown in FIG. 4, it is generated between the non-fragile portion 42b and the moved non-fragile portion 42c as compared with the case of the gas generator 1A in the present embodiment described above. The position where the gap is formed becomes a position closer to the igniter 30, the size of the gap becomes larger, and the spread of the gas generating agent 51 becomes larger. Therefore, by using the gas generator 1B according to this modification, the output characteristics of the gas different from those of the gas generator 1A in the present embodiment described above are shown. Note that the spread of the gas generating agent 51 is schematically represented by broken-line arrows in FIG.

  Even when configured in this manner, the non-fragile portions 42b and 42c remain without being ruptured and melted, so that all of the gas generating agent 51 adjacent to the enhancer cup 40 is not ignited at the same time, It is possible to prevent the gas generating agent 51 from burning rapidly and to intentionally delay the progress of the combustion.

  As described above, according to the present invention, it is possible to control the transmission of energy by the transfer charge by appropriately changing the position of the weakened portion provided in the enhancer cup and the size in the axial direction, and a desired It can be set as the gas generator from which a gas output is obtained.

(Verification test)
5 and 6 show how to adjust the combustion characteristics of the gas generant by applying the present invention by prototyping the gas generators according to Examples 1 and 2 and Comparative Example, respectively, and operating them. It is a graph which shows the result of the test which verified whether it became possible. The graph shown in FIG. 5 shows the tank internal pressure [kPa] on the vertical axis and the time [ms] on the horizontal axis, and the graph shown in FIG. 6 shows the working gas from the gas outlet on the vertical axis. The ejection amount [mol / s] is obtained by taking time [ms] on the horizontal axis. FIG. 7 is a schematic cross-sectional view showing the structure of a gas generator according to a comparative example.

  In the verification test, a gas generator according to Examples 1 and 2 based on the present invention and a gas generator according to a comparative example not based on the present invention were prepared, and these were installed in a hermetically sealed tank of a predetermined capacity. The output performance of each gas generator was evaluated by measuring the pressure in the tank with the passage of time. At that time, the amount of the working gas ejected was calculated based on the gas state equation from the change in the tank pressure. The capacity of the tank used was 60 liters, and the ambient temperature was a room temperature environment (about 23 ° C.). In Examples 1 and 2 and the comparative example, the same amount of the same type of transfer agent and gas generating agent was used, and the structures other than the shape of the enhancer cup were all the same.

  As the gas generator according to the comparative example, a gas generator 1X having a structure shown in FIG. 7 was used. That is, in the gas generator 1X according to the comparative example, the enhancer cup 40 is configured such that the side wall portion 42 is a fragile portion (that is, a non-fragile portion that is not ruptured or melted by the combustion of the explosive 34). Used). In the gas generator 1X according to the comparative example, since all the portions of the side wall portion 42 are configured to be fragile, the spreading of the gas generating agent 51 is caused by the upper end portion, the substantially central portion, and the lower end portion of the fire transfer chamber 44. It progresses radially around everything. Note that the spread of the gas generating agent 51 is schematically represented by broken-line arrows in FIG.

  In the gas generator according to the first embodiment, the enhancer cup 40 made of aluminum is used in the structure shown in FIG. 1 described above, the thickness t2 of the fragile portion 42a is 0.3 mm, and the thicknesses of the non-fragile portions 42b and 42c. t3 and t4 were both 1.0 mm. The position where the fragile portion 42a is provided is a position where the height h shown in FIG. 1 is 6.0 mm, and the size in the axial direction of the fragile portion 42a is 2.2 mm as shown in FIG. It became the size. In addition, the full length along the axial direction of the enhancer cup 40 was 21.5 mm, and the inner diameter was 14.0 mm. Moreover, the thickness t1 of the top wall part 41 was 1.2 mm, and the thickness of the flange part 43 was 1.0 mm.

  In the gas generator according to the second embodiment, the enhancer cup 40 made of aluminum is used in the structure shown in FIG. 1 described above, the thickness t2 of the fragile portion 42a is 0.3 mm, and the thicknesses of the non-fragile portions 42b and 42c. t3 and t4 were both 1.0 mm. The position where the fragile portion 42a is provided is a position where the height h shown in FIG. 1 is 9.0 mm, and the size in the axial direction of the fragile portion 42a is 2.2 mm as shown in FIG. It became the size. In addition, the full length along the axial direction of the enhancer cup 40 was 21.5 mm, and the inner diameter was 14.0 mm. Moreover, the thickness t1 of the top wall part 41 was 1.2 mm, and the thickness of the flange part 43 was 1.0 mm.

  In the gas generator according to the comparative example, in the structure shown in FIG. 7 described above, the aluminum enhancer cup 40 was used, and the thickness t4 of the side wall portion 42 was set to 0.15 mm. In addition, the full length along the axial direction of the enhancer cup 40 was 21.5 mm, and the inner diameter was 14.0 mm. Moreover, the thickness t1 of the top wall part 41 was 0.15 mm, and the thickness of the flange part 43 was 0.18 mm.

  As shown in FIG. 5, in Example 1 and Example 2, it can be seen that the pressure rise is not as steep as the comparative example, and the pressure rises gently. That is, as shown in FIG. 6, in Example 1 and Example 2, a relatively high gas ejection amount is constant after the time when the working gas ejection amount per unit time becomes maximum as compared with the comparative example. It can be seen that it can be obtained over time. In addition, as shown in FIGS. 5 and 6, it can be seen that the degree of pressure rise can be easily controlled by adjusting the position where the weakened portion 42 a is provided.

  From the results of the above verification test, by applying the present invention, it is possible to intentionally delay the progress of the combustion of the gas generating agent in the combustion chamber, so that the gas optimized according to the specifications of the airbag device It was confirmed that a gas generator having an output can be easily manufactured.

  In addition, as shown in FIG. 5, by using the gas generator according to Example 1 and Example 2, the amount of the working gas ejected per unit time is higher than when the gas generator according to the comparative example is used. It was confirmed that the maximum value (that is, the working gas ejection amount around 10 ms) was kept low. This means that the gas generator according to the first and second embodiments can effectively suppress the pressure applied to the housing from becoming larger than necessary. Actually, the amount of deformation along the axial direction of the housing of the gas generators according to Examples 1 and 2 and the comparative example after the verification test (that is, after the operation) was actually measured. In the gas generator according to Example 1, The amount of deformation is reduced to about 70% of the amount of deformation of the gas generator according to the comparative example. In the gas generator according to Example 2, the amount of deformation is the amount of deformation of the gas generator according to the comparative example. It was confirmed that it was reduced to about 80%.

  Therefore, by using the gas generator as in the above-described embodiment and its modifications, a secondary merit that unintentional deformation of the housing during operation can be suppressed can be obtained. Only by reducing the thickness of the housing, it is possible to obtain a merit that the gas generator as a whole can be reduced in weight.

  In the above-described embodiment of the present invention and its modifications, the case where the present invention is applied to a so-called disk-type gas generator has been described as an example, but the scope of application of the present invention is limited to this. It is not a thing.

  As described above, the above-described embodiment and its modifications disclosed herein are illustrative in all respects and are not restrictive. The technical scope of the present invention is defined by the terms of the claims, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  1A, 1B Gas generator, 10 Initiator shell, 11 Bottom plate part, 12 Peripheral wall part, 13 Holding part, 14a, 14b Caulking part, 20 Closure shell, 21 Top plate part, 22 Peripheral wall part, 23 Gas outlet, 24 Seal member , 30 igniter, 31 ignition part, 32 terminal pin, 33 seal member, 34 transfer charge, 40 enhancer cup, 41 top wall part, 42 side wall part, 42a fragile part, 42b, 42c non-fragile part, 43 flange part, 44 Fire transfer chamber, 50 combustion chamber, 51 gas generating agent, 52 closure shell side holding member, 53 cushion material, 54 initiator shell side holding member, 55 filter.

Claims (4)

A short cylindrical housing that includes a combustion chamber in which a gas generating agent is housed, and is constituted by a top plate portion and a bottom plate portion that close the end portion in the axial direction, and a peripheral wall portion provided with a gas jet port;
An igniter including an igniter that is attached to the bottom plate and contains an igniting agent that ignites during operation;
From a single member with a bottomed cylindrical shape that includes a heat transfer chamber in which a charge transfer material is contained, and is disposed so as to protrude toward the combustion chamber so that the heat transfer chamber faces the ignition part. A cup-shaped member
The cup-shaped member has a thin fragile portion that bursts or melts due to combustion of the explosive agent in accordance with the operation of the igniter, and a side wall portion that partitions the transfer chamber and the combustion chamber, and the operation of the igniter A thick non-fragile portion that remains without rupturing and melting even by the combustion of the above-mentioned transfer charge,
The fragile portion is provided in an annular shape along the circumferential direction of the cup-shaped member at an intermediate position of the side wall portion in the axial direction of the cup-shaped member, and along the axial direction of the cup-shaped member by the non-fragile portion. A gas generator located between the two.   The gas generator according to claim 1, wherein the fragile portion is configured by a groove provided on an outer peripheral surface of the side wall portion of the cup-shaped member.   The gas generation according to claim 1 or 2, wherein the cup-shaped member is configured such that the intermediate position is positioned on the top plate portion side of the ignition portion along the axial direction of the cup-shaped member. vessel.   The gas generator according to any one of claims 1 to 3, wherein the cup-shaped member is a press-molded product made of aluminum or aluminum alloy.

Images