Gas generator

Abstract

To provide a gas generator capable of achieving both of reduction in weight and reduction in manufacturing cost while maintaining good gas output characteristics.SOLUTION: A gas generator 1A includes: an igniter 40 assembled to one end portion of a housing; a gas generating agent 70 arranged inside the housing; and a coil spring 80 interposed between the one end portion of the housing and the gas generating agent 70. The coil spring 80 serves to fix the gas generating agent 70 inside the housing by energizing the gas generating agent 70 toward the other end portion of the housing while putting the gas generating agent away from the igniter 40. The coil spring 80 is arranged substantially coaxially with an ignition portion 41 to surround the ignition portion 41 without interposition of another member between the coil spring and the ignition portion 41, so as to restrict a degree of opening of a cup body 41c included in the ignition portion 41 of the igniter 40 at the time of cleavage of the cup body 41c.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a gas generator to be incorporated in an airbag device as an occupant protection device equipped in an automobile or the like, and in particular to a so-called cylindrical gas generator having an elongated cylindrical outer shape which can be suitably incorporated in a side airbag device or the like. [Background technology]

[0002] Conventionally, airbag devices, which are passenger protection devices, have become widespread from the viewpoint of protecting passengers in automobiles, etc. Airbag devices are installed for the purpose of protecting passengers from impacts that occur when a vehicle or the like crashes, and the airbag instantly inflates and deploys when a vehicle or the like crashes, so that the airbag acts as a cushion to receive the body of the passenger.

[0003] The gas generator is a device incorporated into the airbag device. When a vehicle crashes, an igniter is ignited by electrical current from a control unit. The flame produced in the igniter burns a gas generating agent, instantly generating a large amount of gas, which inflates and deploys the airbag.

[0004] There are gas generators of various configurations based on the specifications of the installation position relative to the vehicle, output, etc. One of them is called a cylinder-type gas generator. The cylinder-type gas generator has a long cylindrical outer shape and is suitably incorporated into a side airbag device, a curtain airbag device, a knee airbag device, a seat cushion airbag device, etc.

[0005] Typically, in a cylinder-type gas generator, an igniter is attached to one axial end of a housing, and a combustion chamber containing a gas generating agent is provided on the one end side, a filter chamber containing a filter is provided on the other axial end side of the housing, and a gas outlet is provided on the peripheral wall of the housing in a part that defines the filter chamber.

[0006] In a cylindrical gas generator configured in this manner, gas generated in the combustion chamber flows into the filter chamber along the axial direction of the housing, passing through the inside of the filter, and the gas after passing through the filter is ejected to the outside via the gas outlet.

[0007] In general, it is important that the gas generating agent in a gas generator is hermetically sealed from the outside, because if the gas generating agent absorbs moisture, it may not be possible to obtain the desired gas output characteristics.

[0008] In a cylinder-type gas generator, one method for preventing the gas generating agent from absorbing moisture is to store the gas generating agent in a sealed container made of a relatively fragile material that melts or bursts due to heat or pressure generated by the activation of an igniter, and to place this inside the housing. A cylinder-type gas generator employing this method is disclosed, for example, in JP 2018-69924 A (Patent Document 1).

[0009] In the cylinder-type gas generator disclosed in the above-mentioned Patent Document 1, a coil spring is provided between the sealed container arranged inside the housing and the one end of the housing to which the igniter is assembled, for biasing the sealed container toward the other end of the housing. The coil spring is for fixing the sealed container inside the housing while maintaining an appropriate distance from the igniter assembled to the one end of the housing to the gas generating agent contained in the sealed container.

[0010] In the gas generator disclosed in Patent Document 1, a substantially cylindrical metallic combustion control cover is provided on the one end side of the housing so as to cover the ignition part of the igniter, which is the part that contains the ignition charge. The combustion control cover is for efficiently guiding the thermal particles generated by the igniter during operation to the gas generating agent, and more specifically, for imparting directionality to the traveling direction of the thermal particles generated by the ignition part.

[0011] By using a cylindrical gas generator having such a configuration, it is possible to obtain good gas output characteristics during operation. [Prior art documents] [Patent documents]

[0012] [Patent Document 1] JP 2018-69924 A Summary of the Invention [Problem to be solved by the invention]

[0013] However, in the case of a cylindrical gas generator having the above-mentioned configuration, it is necessary to provide a large number of parts at the above-mentioned one end side portion of the housing, which not only increases the number of parts but also complicates the assembly work, resulting in a problem of increased manufacturing costs. Furthermore, if the number of parts can be reduced, the weight of the gas generator as a whole can be reduced accordingly.

[0014] Therefore, the present invention has been made in consideration of the above-mentioned problems, and has an object to provide a gas generator that enables weight reduction and reduction in manufacturing costs while maintaining good gas output characteristics. [Means for solving the problem]

[0015] A gas generator according to the present invention includes a housing, a gas generating agent, an igniter, and a coil spring. The housing is a long cylindrical member having a peripheral wall portion whose one end and the other end in the axial direction are closed. The gas generating agent is disposed inside the housing. The igniter has an ignition portion in which an ignition charge for burning the gas generating agent is accommodated, and is attached to the one end of the housing so that the ignition portion is positioned to project toward the inside of the housing. The coil spring is interposed between the one end of the housing and the gas generating agent, and is a member for fixing the gas generating agent inside the housing by biasing the gas generating agent toward the other end of the housing while separating the gas generating agent from the ignition portion. The ignition portion includes a cup body that is cleaved by ignition of the ignition charge when the igniter is activated. In the gas generator based on the present invention, the coil spring is arranged approximately coaxially with the ignition portion so as to surround the ignition portion without any other member being interposed between the coil spring and the ignition portion, so that the degree of opening of the cup body when the cup body is ruptured is regulated by the coil spring.

[0016] In the gas generator according to the present invention, the ignition portion may have a substantially cylindrical outer shape, in which case the coil spring may have a substantially cylindrical outer shape.

[0017] In the gas generator based on the present invention, a surrounding portion which is a portion of the coil spring that surrounds the ignition portion may be in non-contact with the ignition portion.

[0018] In the gas generator based on the present invention, a surrounding portion which is a portion of the coil spring surrounding the ignition portion may be in contact with the ignition portion. Effect of the Invention

[0019] According to the present invention, it is possible to provide a gas generator that enables weight reduction and reduction in manufacturing costs while maintaining good gas output characteristics. [Brief description of the drawings]

[0020] [Figure 1] 1 is a schematic diagram of a cylinder-shaped gas generator according to a first embodiment. [Diagram 2] 2 is an enlarged cross-sectional view of the vicinity of an igniter of the cylinder-shaped gas generator shown in FIG. 1. [Diagram 3] 2 is an enlarged cross-sectional view of the vicinity of a partition member of the cylinder-shaped gas generator shown in FIG. 1. [Figure 4] 5A to 5C are views for explaining a preferable range of clearance in the cylinder-shaped gas generator according to the embodiment. [Diagram 5] FIG. 4 is an enlarged cross-sectional view of the vicinity of an igniter, showing an example of a modified example of the cylinder-shaped gas generator according to the first embodiment. [Figure 6] 11 is an enlarged cross-sectional view of the vicinity of an igniter of a cylinder-shaped gas generator according to a second embodiment. FIG. [Figure 7] 11 is an enlarged cross-sectional view of the vicinity of an igniter of a cylinder-shaped gas generator according to a third embodiment. FIG. [Figure 8] 4 is an enlarged cross-sectional view of the vicinity of an igniter of a cylinder-shaped gas generator according to Comparative Example 1. FIG. [Figure 9] 1 is a table showing test conditions and test results of a verification test. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. The embodiment shown below illustrates a case where the present invention is applied to a cylinder-type gas generator incorporated in a side airbag device. In the embodiment shown below, the same or common parts are given the same reference numerals in the drawings, and the description thereof will not be repeated.

[0022] (Embodiment 1) Fig. 1 is a schematic diagram of a cylinder-shaped gas generator according to embodiment 1. Figs. 2 and 3 are enlarged sectional views of the vicinity of an igniter and the vicinity of a partition member, respectively, of the cylinder-shaped gas generator shown in Fig. 1. First, with reference to Figs. 1 to 3, the configuration of cylinder-shaped gas generator 1A according to the present embodiment will be described.

[0023] 1, cylinder-shaped gas generator 1A according to this embodiment has a long, cylindrical outer shape and has a long, cylindrical housing with one axial end and the other end closed. The housing includes housing main body 10, holder 20, and closing member 30.

[0024] The housing, which is made up of the housing main body 10, the holder 20, and the closing member 30, contains internal components such as the igniter 40, the partition member 50, the sealed container 60, the gas generating agent 70, the autoignition agent 71, the partition member 72, the spring-like member 73, the coil spring 80, and the filter 90. Also, the housing contains a combustion chamber S1 in which the gas generating agent 70, one of the internal components described above, is mainly disposed, and a filter chamber S2 in which the filter 90 is disposed.

[0025] The housing body 10 constitutes the peripheral wall of the housing and is made of a long cylindrical member with openings formed at both axial ends. The holder 20 is made of a tubular member having a through-hole 21 extending in the same direction as the axial direction of the housing body 10, and has an annular groove 22 for crimping on its outer circumferential surface, which will be described later. The closing member 30 is made of a disk-shaped member having a predetermined thickness, and has an annular groove 31 for crimping on its outer circumferential surface, which will be described later. These annular grooves 22, 31 for crimping are both formed on the outer circumferential surface of the holder 20 and the peripheral surface of the closing member 30 so as to extend in the circumferential direction.

[0026] The housing body 10 may be made of a metal member such as stainless steel, iron steel, aluminum alloy, stainless alloy, etc., or may be made of a press-formed product formed into a cylindrical shape by pressing a rolled steel plate such as SPCE. The housing body 10 may also be made of an electric resistance welded pipe such as STKM.

[0027] In particular, when the housing body 10 is constructed from a press-formed rolled steel plate or an electric resistance welded pipe, the housing body 10 can be formed more cheaply and easily than when metal components such as stainless steel or steel are used, and the weight can be significantly reduced.

[0028] On the other hand, the holder 20 and the blocking member 30 are made of metal members such as stainless steel, iron steel, aluminum alloy, stainless alloy, or the like.

[0029] The holder 20 is fixed to the housing body 10 so as to close one axial open end of the housing body 10. Specifically, with the holder 20 inserted into the one open end of the housing body 10, a portion of the housing body 10 corresponding to an annular groove portion 22 provided on the outer circumferential surface of the holder 20 is reduced in diameter radially inward and engaged with the annular groove portion 22, thereby crimping and fixing the holder 20 to the housing body 10. As a result, one axial end of the housing is constituted by the holder 20.

[0030] The closing member 30 is fixed to the housing body 10 so as to close the other axial opening end of the housing body 10. Specifically, with the closing member 30 inserted into the other opening end of the housing body 10, a portion of the housing body 10 corresponding to annular groove portion 31 provided on the circumferential surface of the closing member 30 is reduced in diameter radially inward and engaged with the annular groove portion 31, thereby crimping and fixing the closing member 30 to the housing body 10. As a result, the other axial end of the housing is constituted by the closing member 30.

[0031] These crimping fixations are called eight-way crimping, which reduces the diameter of the housing body 10 almost uniformly inward in the radial direction. By performing this eight-way crimping, the housing body 10 is provided with crimped portions 12 and 13. As a result, the crimped portions 12 and 13 come into direct contact with the annular grooves 22 and 31, respectively, preventing the occurrence of gaps between them.

[0032] The assembly structure of the holder 20 and the closing member 30 to the housing main body 10 is not limited to the above-mentioned assembly structure, and other assembly structures may be adopted. Also, the housing main body 10 and the closing member 30 may not be separate bodies, but may be configured as one member having a bottomed cylindrical shape.

[0033] 1 and 2, the igniter 40 is mounted to the one end in the axial direction of the housing by being supported by the holder 20. The igniter 40 is for burning the gas generating agent 70, and is installed so as to face the space inside the housing.

[0034] The igniter 40 includes an ignition section 41 and a pair of terminal pins 42. The ignition section 41 includes an ignition charge 41a, a plug 41b, and a cup body 41c, and the ignition charge 41a is accommodated in the ignition section 41 by being disposed in a space defined by the plug 41b and the cup body 41c. A resistor (bridge wire) is attached inside the ignition section 41 so as to connect to the pair of terminal pins 42, and the ignition section 41 is filled with an ignition charge 41a so as to surround the resistor or to be in contact with the resistor. A transfer charge may be loaded into the ignition section 41 as necessary.

[0035] Here, the resistor is generally a nichrome wire or a resistance wire made of an alloy containing platinum and tungsten, and the ignition charge is generally ZPP (zirconium potassium perchlorate), ZWPP (zirconium tungsten potassium perchlorate), lead tricinate, etc. The transfer charge is generally a composition made of metal powder / oxidizer, such as B / KNO3, B / NaNO3, Sr(NO3)2, etc., a composition made of titanium hydride / potassium perchlorate, or a composition made of B / 5-aminotetrazole / potassium nitrate / molybdenum trioxide. The cup body 41c provided in the ignition unit 41 includes a metal cup.

[0036] When a collision is detected, a predetermined amount of current flows through the resistor via the terminal pin 42. When a predetermined amount of current flows through the resistor, Joule heat is generated in the resistor, and the ignition charge 41a starts to burn. High-temperature heat particles generated by the combustion split open the cup body 41c that contains the ignition charge 41a. The time from when the current flows through the resistor to when the igniter 40 is activated is generally 2 milliseconds or less when a nichrome wire is used for the resistor.

[0037] The igniter 40 is fixed to the holder 20 by a crimping portion 23 provided on the holder 20. More specifically, the holder 20 has the crimping portion 23 for crimping and fixing the igniter 40 at an axial end portion facing the space inside the housing, and the igniter 40 is inserted into the through-hole 21 and abutted against a wall portion of a portion of the holder 20 that defines the through-hole 21, and the above-mentioned crimping portion 23 is crimped in such a state that the igniter 40 is clamped and fixed to the holder 20.

[0038] As a result, the igniter 40 is attached to the holder 20 so that the ignition portion 41 is positioned to protrude toward the inside of the housing. Therefore, when the igniter 40 is activated, the ignition charge 41a is ignited, causing the cup body 41c to split, and the cup body 41c opens along with the split.

[0039] A recess 24 is provided at the axial end portion exposed to the outside of the holder 20, which is continuous with the above-mentioned through-hole 21. The recess 24 forms a female connector portion that receives a male connector (not shown) of a harness for connecting the igniter 40 to a control unit (not shown), and a portion of the terminal pin 42 of the igniter 40 near the tip is exposed and positioned within the recess 24. A male connector is inserted into the recess 24 as the female connector portion, thereby achieving electrical continuity between the core wire of the harness and the terminal pin 42.

[0040] 1 and 3, a partition member 50 is disposed at a predetermined position in the space inside the housing. The partition member 50 is a member for dividing the space inside the housing in the axial direction into a combustion chamber S1 and a filter chamber S2.

[0041] The partition member 50 has a cylindrical shape with a bottom, and is made of a metal member such as stainless steel, iron steel, aluminum alloy, stainless alloy, etc. The partition member 50 has a flat partition wall portion 51 arranged perpendicular to the axial direction of the housing body 10, and a cylindrical plate-like annular wall portion 52 standing on the periphery of the partition wall portion 51. The partition member 50 is arranged so that the outer main surface of the partition wall portion 51 abuts against the filter 90, and the outer peripheral surface of the annular wall portion 52 abuts against the inner peripheral surface of the housing body 10.

[0042] A score 51a is provided on the main surface of the partition wall portion 51 that contacts the filter 90. The score 51a is for causing the partition wall portion 51 to break and form an opening in response to an increase in the internal pressure of the combustion chamber S1 due to combustion of the gas generating agent 70, and is configured, for example, with a plurality of grooves that are provided radially and intersect with each other. The score 51a is provided in a portion of the filter 90 that faces the hollow portion 91.

[0043] 1 to 3, within the space inside the housing, a space sandwiched between the holder 20 and the partition member 50 (i.e., combustion chamber S1) contains a sealed container 60 and a coil spring 80. Furthermore, a gas generating agent 70, an autoignition agent 71, a partition member 72, and a spring-like member 73 are contained in a gas generating agent storage chamber S1A, which is the space inside the sealed container 60.

[0044] The sealed container 60 is for sealing the gas generating agent 70 contained therein, and is made of a fragile material that melts or bursts due to the heat or pressure generated by the activation of the igniter 40. The sealed container 60 has a generally cylindrical shape with both ends closed, and is disposed generally coaxially with the housing.

[0045] More specifically, the sealed container 60 includes a container body 61 and a lid body 62, and the container body 61 and the lid body 62 are joined together to form the above-mentioned gas generating agent storage chamber S1A inside the sealed container 60.

[0046] The container body 61 has a flat top wall portion 61a and a cylindrical side wall portion 61b extending from the periphery of the top wall portion 61a. The lid body 62 has a flat bottom portion 62a located inside the container body 61 by being inserted into the opening end 61b1 of the container body 61, and a rolled-up portion 62b extending from the periphery of the bottom portion 62a and partially curved to cover the inner circumferential surface, end face and outer circumferential surface of the opening end 61b1 of the container body 61.

[0047] Here, the above-mentioned container body 61 and lid body 62 are joined between the opening end 61b1 of the container body 61 and the rolled-up portion 62b of the lid body 62 provided to cover the opening end 61b1. More specifically, the first crimping portion 62b1 and the second crimping portion 62b2 are provided on the rolled-up portion 62b provided to cover the opening end 61b1 of the container body 61, thereby realizing the joining of the container body 61 and the lid body 62. Both the first crimping portion 62b1 and the second crimping portion 62b2 are formed by reducing the diameter of a predetermined portion of the container body 61 radially inward.

[0048] As described above, both the container body 61 and the lid body 62 are made of a fragile material that melts or bursts due to heat or pressure generated by activation of the igniter 40. More specifically, the lid body 62 is made of a fragile material that melts or bursts due to heat or pressure generated by the combustion of the ignition charge 41a or, in addition, the transfer charge when the igniter 40 is activated and the gas generating agent 70 is burned, and the container body 61 is made of a fragile material that melts or bursts due to heat or pressure generated by the combustion of the gas generating agent 70 when the igniter 40 is activated and the gas generating agent 70 is burned.

[0049] Specifically, the container body 61 and the lid body 62 are preferably constructed as press-formed products made of metal such as copper, aluminum, a copper alloy, an aluminum alloy, or the like, and by joining these together as described above, the gas generating agent 70 contained therein is hermetically sealed from the outside.

[0050] The sealed container 60 is inserted into the housing body 10 so that the top wall portion 61a of the container body 61 is located on the partition member 50 side and the bottom portion 62a of the lid body 62 is located on the holder 20 side. As a result, the bottom portion 62a of the lid body 62 faces the ignition portion 41 of the igniter 40.

[0051] More specifically, the end of the sealed container 60 on the side where the top wall portion 61a is located is inserted into the partition member 50 and thereby fitted into the partition member 50, and the end of the sealed container 60 on the side where the bottom portion 62a is located is loosely fitted into the housing main body 10. As a result, the sealed container 60 is positioned and fixed with respect to the housing main body 10, and is disposed a predetermined distance away from the inner peripheral surface of the housing main body 10.

[0052] Therefore, an insulating layer S1B, which is a space of a predetermined size, is formed between the housing main body 10, which constitutes the peripheral wall portion of the housing, and the side wall portion 61b of the sealed container 60, and the insulating layer S1B extends in an approximately cylindrical shape along the axial direction of the combustion chamber S1.

[0053] In this way, by providing a cylindrical insulating layer S1B between the sealed container 60 containing the gas generating agent 70 and the housing body 10, even if a fire or the like occurs in a vehicle or the like equipped with an airbag device in which the cylindrical gas generator 1A is incorporated, the gas generating agent 70 can be effectively prevented from being heated from the outside and rising in temperature.

[0054] That is, by providing the insulating layer S1B in the radially outer portion of the sealed container 60 containing the gas generating agent 70, the insulating layer S1B acts as a thermal resistor, making it difficult for heat from the housing main body 10 to be transferred to the gas generating agent 70, and the temperature of the gas generating agent 70 can be kept relatively low when auto-ignition operation, which is initiated by the automatic ignition of the auto-ignition agent 71 described below, occurs. Therefore, it is possible to significantly suppress the rise in the internal pressure of the housing during auto-ignition operation.

[0055] Here, the insulating layer S1B preferably has a thermal conductivity lower than that of the housing body 10, and in this embodiment, is configured as an air layer. However, the insulating layer S1B does not necessarily have to be an air layer, and may be configured as a gas layer filled with another gas, or may be configured as a vacuum layer. Furthermore, the insulating layer S1B may be configured by disposing various types of insulating members in the space.

[0056] Of the gas generating agent storage chamber S1A formed inside the sealed container 60, an autoignition agent 71 and a partition member 72 are disposed at the end on the partition member 50 side, and a spring-like member 73 is disposed at the end on the holder 20 side. Meanwhile, of the gas generating agent storage chamber S1A formed inside the sealed container 60, gas generating agent 70 is disposed in a portion excluding the end on the partition member 50 side and the end on the holder 20 side.

[0057] The gas generating agent 70 is an agent that generates gas by being ignited and burned by thermal particles generated by the activation of the igniter 40. As the gas generating agent 70, it is preferable to use a non-azide gas generating agent, and the gas generating agent 70 is generally configured as a molded body containing a fuel, an oxidizer, and an additive.

[0058] The fuel may be, for example, a triazole derivative, a tetrazole derivative, a guanidine derivative, an azodicarbonamide derivative, a hydrazine derivative, or a combination of these. Specifically, for example, nitroguanidine, guanidine nitrate, cyanoguanidine, 5-aminotetrazole, or the like is preferably used.

[0059] Examples of the oxidizing agent include basic metal salts such as basic copper nitrate and basic copper carbonate, perchlorates such as ammonium perchlorate and potassium perchlorate, and nitrates containing a cation selected from alkali metals, alkaline earth metals, transition metals, and ammonia. Examples of the nitrates that are preferably used include sodium nitrate and potassium nitrate.

[0060] Examples of additives include binders, slag formers, and combustion control agents. As binders, for example, organic binders such as metal salts of carboxymethylcellulose and stearates, and inorganic binders such as synthetic hydrotalcite and acid clay can be suitably used. As slag formers, silicon nitride, silica, acid clay, etc. can be suitably used. As combustion control agents, metal oxides, ferrosilicon, activated carbon, graphite, etc. can be suitably used.

[0061] The shape of the molded body of the gas generating agent 70 may be granular, pellet-like, cylindrical, or other granular, or disk-like. In addition, for cylindrical molded bodies, perforated molded bodies having through holes inside the molded body (for example, a single-hole cylindrical shape or a multi-hole cylindrical shape) may also be used. These shapes are preferably selected appropriately according to the specifications of the airbag device in which the cylindrical gas generator 1A is incorporated, and it is preferable to select an optimal shape according to the specifications, such as a shape in which the gas generation rate changes over time when the gas generating agent 70 is burned. In addition to the shape of the gas generating agent 70, it is preferable to appropriately select the size and filling amount of the molded body taking into consideration the linear burning rate and pressure exponent of the gas generating agent 70.

[0062] Autoignition agent 71 is an agent that ignites automatically without depending on the operation of igniter 40, and in this embodiment is made up of pellets formed into a flattened, generally cylindrical shape. Autoignition agent 71 ignites spontaneously at a lower temperature than gas generating agent 70, and is intended to prevent abnormal operation of cylinder-shaped gas generator 1A from being induced by external heating in the unlikely event of a fire or the like occurring in a vehicle or the like equipped with an airbag device in which cylinder-shaped gas generator 1A is incorporated.

[0063] The partitioning member 72 is a member for partitioning the gas generating agent storage chamber S1A in the axial direction of the housing. The partitioning member 72 has a positioning recess 72a in a portion of the peripheral wall of the housing body 10 that faces the partition member 50 in the axial direction, and has a skirt-shaped fixing tubular portion 72b on its outer edge. In addition, a single or multiple through holes 72c are provided in the bottom of the positioning recess 72a of the partitioning member 72 for mutual communication between a pair of spaces partitioned by the partitioning member 72 (i.e., the space containing the gas generating agent 70 and the space containing the autoignition agent 71).

[0064] Here, the partition member 72 is preferably configured as a press-molded metal product, for example, a brass member that will not break or melt even when the gas generating agent 70 is burned. However, the partition member 72 does not necessarily have to be made of brass, and the partition member 72 may be formed of stainless steel, steel, iron, aluminum, an aluminum alloy, or the like.

[0065] The partition member 72 does not necessarily need to be provided with the through-hole 72c, and may be configured so that a through-hole is formed in the partition member 72 as the gas generating agent 70 burns by providing a score in the partition member 72. Also, the partition member 72 itself may be configured from a fragile material that breaks or melts due to the combustion of the gas generating agent 70, without providing a through-hole or a score in the partition member 72.

[0066] The partitioning member 72 is inserted into the side wall portion 61b of the container body 61 of the sealed container 60, and the fixing tube portion 72b of the partitioning member 72 abuts against the inner circumferential surface of the side wall portion 61b. In other words, the partitioning member 72 is press-fitted into the side wall portion 61b of the container body 61, whereby the partitioning member 72 is fixed to the sealed container 60.

[0067] A portion of the autoignition agent 71 formed in a pellet shape is accommodated in the positioning recess 72a provided in the partition member 72. As a result, the autoignition agent 71 is sandwiched between the bottom of the positioning recess 72a of the partition member 72 and the top wall portion 61a of the container body 61. Therefore, the autoignition agent 71 comes into contact with both the partition member 72 and the container body 61.

[0068] By configuring in this manner, the autoignition agent 71 comes into thermal contact with the housing body 10 via the partition member 72, which is a metallic member, the end portion of the sealed container 60 near the top wall portion 61a, which is also a metallic member, and the partition member 50, which is also a metallic member, in substantially the shortest possible path.

[0069] Therefore, in the event of a fire or the like occurring in a vehicle or the like, the timing of occurrence of the auto-ignition operation that is initiated by the automatic ignition of the auto-ignition agent 71 is accelerated, and as a result, the temperature of the gas generating agent 70 when the auto-ignition operation occurs can be kept relatively low. Therefore, it becomes possible to significantly suppress the rise in the internal pressure of the housing during the auto-ignition operation.

[0070] The spring-like member 73 is provided for the purpose of preventing the gas generating agent 70 made of a molded body from being crushed by vibration or the like, and has a spring portion 73a and a pressing portion 73b formed by bending a metal wire. The spring portion 73a is disposed so that one end thereof abuts against the bottom portion 62a of the sealed container 60, and the pressing portion 73b is formed at the other end. The pressing portion 73b is formed, for example, by arranging metal wires approximately in parallel at a predetermined interval, and abuts against the gas generating agent 70.

[0071] As a result, the gas generating agent 70 is elastically biased by the spring-like member 73 toward the partition member 50 side, and is prevented from moving inside the sealed container 60. Note that, instead of the above-mentioned spring-like member 73, a cushioning material made of a member such as a ceramic fiber molded body, rock wool, foamed resin (e.g., foamed silicone, foamed polypropylene, foamed polyethylene, etc.), chloroprene, and rubber such as EPDM may be used.

[0072] In the space of the combustion chamber S1 located closer to the holder 20 than the sealed container 60, a coil spring 80, which is a separate part from the above-mentioned spring-like member 73, is disposed. The coil spring 80 is formed by winding a metal wire in a spiral shape, and unlike the above-mentioned spring-like member 73, does not have a pressing portion 73b as the spring-like member 73 has. In this embodiment, the metal wire is wound so as to have the same inner diameter at any position in the axial direction, so that the coil spring 80 has a substantially cylindrical outer shape as a whole.

[0073] The coil spring 80 is a member for fixing the sealed container 60 inside the housing while absorbing dimensional variations of various components housed inside the housing. The coil spring 80 also serves to properly maintain the distance from the igniter 40 attached to one end of the housing to the gas generating agent 70 housed in the sealed container 60.

[0074] Therefore, the coil spring 80 is interposed between the one end of the housing in the axial direction and the sealed container 60, with one end of the coil spring 80 being arranged to abut against the holder 20 and / or the igniter 40, and the other end being arranged to abut against the end of the sealed container 60 on the holder 20 side. As a result, the sealed container 60 is elastically biased by the coil spring 80 toward the partition member 50 side, which is the other end side of the housing in the axial direction, and is fixed to the housing by being sandwiched between the partition member 50 and the coil spring 80.

[0075] Here, the coil spring 80 is arranged so as to surround the ignition portion 41 of the igniter 40, which has a substantially cylindrical outer shape. More specifically, the coil spring 80 is arranged substantially coaxially with the ignition portion 41 so as to surround the ignition portion 41 without any other member being interposed between the coil spring 80 and the ignition portion 41. As a result, the coil spring 80 includes a wound-shaped surrounding portion 81 that surrounds the ignition portion 41, and an extending portion 82 that is also wound and is located closer to the sealed container 60 than the surrounding portion 81 (see FIG. 4).

[0076] By configuring it in this manner, when the cup body 41c of the ignition portion 41 is torn open upon activation of the igniter 40, the degree to which the cup body 41c opens is regulated by the coil spring 80, the details of which will be described later.

[0077] 1, within the space inside the housing, a filter 90 is disposed in a space sandwiched between the closing member 30 and the partition member 50 (i.e., filter chamber S2). The filter 90 is made of a cylindrical member having a hollow portion 91 extending in the same direction as the axial direction of the housing body 10, with one axial end face abutting against the closing member 30 and the other axial end face abutting against the partition member 50.

[0078] The filter 90 functions as a cooling means for cooling the gas by removing the high temperature heat of the gas generated by the combustion of the gas generating agent 70 as the gas passes through the filter 90, and also functions as a removal means for removing slag (residue) and the like contained in the gas. By using the filter 90 made of a cylindrical member as described above, the flow resistance to the gas flowing through the filter chamber S2 during operation is kept low, making it possible to realize an efficient gas flow.

[0079] The filter 90 may be made of an assembly of metal wires or metal mesh materials, preferably made of stainless steel, steel, etc. Specifically, a knitted wire mesh, a plain woven wire mesh, an assembly of crimped woven metal wires, or a combination of these compressed by a press may be used.

[0080] Also, a perforated metal sheet wound around the filter 90 can be used. In this case, the perforated metal sheet can be, for example, an expanded metal sheet made by cutting a metal sheet in a zigzag pattern and expanding the cuts to form holes and process it into a mesh-like shape, or a hook metal sheet made by drilling holes in a metal sheet and flattening the metal sheet by crushing burrs that are generated around the edges of the holes.

[0081] A portion of the housing body 10 that defines the filter chamber S2 is provided with a plurality of gas outlets 11 arranged in the circumferential and axial directions. These gas outlets 11 are for directing the gas that has passed through the filter 90 to the outside of the housing.

[0082] Next, with reference to FIG. 1, an operation during operation of cylinder-shaped gas generator 1A according to the present embodiment will be described.

[0083] Referring to FIG. 1, when a vehicle equipped with a cylinder-shaped gas generator 1A according to this embodiment collides, the collision is detected by a collision detection means provided separately in the vehicle, and based on this, igniter 40 is activated by the passage of electricity from a control unit provided separately in the vehicle.

[0084] When the igniter 40 is activated, the pressure inside the ignition section 41 increases due to the combustion of the ignition charge 41a or, in addition, the transfer charge, causing the cup body 41c of the ignition section 41 to split open, and the thermal particles generated by the combustion of the ignition charge 41a flow out to the outside of the ignition section 41.

[0085] The thermal particles flowing out from the ignition part 41 are given directionality by the coil spring 80 described above, and reach the bottom 62a of the sealed container 60. As a result, the bottom 62a of the sealed container 60 melts or bursts due to the heat or pressure generated by the activation of the igniter 40, and the thermal particles described above reach the gas generating agent 70.

[0086] The thermal particles reaching the gas generating agent 70 combust the gas generating agent 70, thereby generating a large amount of gas. As a result, the pressure and temperature in the gas generating agent storage chamber S1A rise, the side wall portion 61b of the sealed container 60 ruptures or melts, the autoignition agent 71 burns, and further the top wall portion 61a of the sealed container 60 ruptures or melts.

[0087] As the gas generating agent 70 burns, the pressure in the entire combustion chamber S1 further increases, and when the internal pressure of the combustion chamber S1 reaches a predetermined pressure, a break occurs in the portion of the partition member 50 where the score 51a is provided. As a result, a communication hole is formed in the partition member 50 in the portion facing the hollow portion 91 of the filter 90, and the combustion chamber S1 and the filter chamber S2 are in communication with each other via the communication hole.

[0088] Accordingly, gas generated in the combustion chamber S1 flows into the filter chamber S2 through the communication holes formed in the partition member 50. The gas that flows into the filter chamber S2 flows along the axial direction in the hollow portion 91 of the filter 90, then turns toward the radial direction, and flows through the inside of the filter 90. At that time, the filter 90 removes heat and cools the gas, and the filter 90 removes slag contained in the gas.

[0089] Then, the gas after passing through filter 90 is ejected to the outside of the housing through gas ejection port 11. The ejected gas is introduced into the inside of an airbag provided adjacent to cylindrical gas generator 1A, and inflates and deploys the airbag.

[0090] Here, as shown in FIG. 2, in cylinder-shaped gas generator 1A of the present embodiment, as described above, coil spring 80 interposed between one axial end of the housing (i.e., holder 20) and sealed container 60 is arranged approximately coaxially with ignition portion 41 of igniter 40 so as to surround ignition portion 41 with no other members interposed between them.

[0091] With this configuration, firstly, since the ignition portion 41 is surrounded by the surrounding portion 81 (see FIG. 4) of the coil spring 80, when the cup body 41c of the ignition portion 41 is cleaved, it is possible to suppress the side wall portion of the cup body 41c from being cleaved or from being deformed outward. Therefore, it is possible to make it possible to form an opening mainly at the tip portion, which is the portion of the cup body 41c located on the gas generating agent 70 side.

[0092] Secondly, when the cup body 41c of the ignition part 41 is split open to form an opening at the tip of the cup body 41c, the open part of the cup body 41c comes into contact with the extension part 82 (see FIG. 4) of the coil spring 80, and further outward deformation can be suppressed. Therefore, the extension part 82 of the coil spring 80 and the open part of the cup body 41c function as a kind of guide that determines the direction of travel of the thermal particles.

[0093] Therefore, the traveling direction of the thermal particles generated in the ignition portion 41 is narrowed to the axial direction of the housing main body 10, and the thermal particles can be efficiently guided to the gas generating agent 70. Therefore, the coil spring 80 not only functions to fix the above-mentioned sealed container 60 inside the housing, but also functions to efficiently guide the thermal particles generated in the igniter 40 during activation to the gas generating agent 70, eliminating the need for a member such as a combustion control cover that was previously required.

[0094] In this way, by using cylinder-shaped gas generator 1A according to the present embodiment, it is possible to reduce the number of parts compared to conventional techniques, which not only simplifies the assembly work but also reduces the weight of the gas generator as a whole. Therefore, it is possible to achieve both weight reduction and reduced manufacturing costs while maintaining good gas output characteristics.

[0095] In order to efficiently guide the thermal particles generated in the ignition portion 41 to the gas generating agent 70, it is necessary to provide the thermal particles with an appropriate degree of directionality, and the degree of directionality provided to the thermal particles is determined in particular by the clearance between the ignition portion 41 and the surrounding portion 81, which is the portion of the coil spring 80 that surrounds the ignition portion 41. A preferred range of this clearance will be described below with reference to Fig. 4. Fig. 4 is a diagram for explaining a preferred range of clearance in the cylinder-type gas generator according to the present embodiment.

[0096] From the viewpoint of preventing cracks or deformations from occurring in the side wall portion of the cup body 41c, it is preferable that there is no clearance between the ignition portion 41 and the surrounding portion 81. However, it is not always easy to press-fit the coil spring 80 made of a metal wire into the ignition portion 41, and from the viewpoint of facilitating the assembly work, it is desirable to provide a slight clearance.

[0097] From the results of the verification test described later, it has been confirmed that this clearance is preferably at least 1.0 [mm] or less. However, the upper limit thereof can be determined as follows, taking into account that the extended portion 82 and the open portion of the cup body 41c also function as a kind of guide.

[0098] That is, referring to FIG. 4, when the inner diameter of the gas generating agent housing chamber S1A is R1, the outer diameter of the ignition portion 41 is R2, the distance along the axial direction of the housing body 10 from the portion of the ignition portion 41 where the ignition charge 41a is accommodated to the gas generating agent housing chamber S1A is L1, and the distance along the axial direction of the housing body 10 from the portion of the ignition portion 41 where the ignition charge 41a is accommodated to the sealed container 60 is L2, the clearance C between the ignition portion 41 and the surrounding portion 81 preferably satisfies the condition of 0 < C ≤ (R1 - R2) × (L2 / L1) / 2.

[0099] By satisfying the above conditions, when viewed from the ignition portion 41, the gas generating agent housing chamber S1A is positioned within the range where the hot particles are guided by the extended portion 82 and the open portion of the cup body 41c. Therefore, the hot particles can be guided to the gas generating agent housing chamber S1A very efficiently. Therefore, in order to surely obtain the above-described effects, it is preferable that the above conditions are satisfied.

[0100] FIG. 5 is an enlarged cross-sectional view near the igniter showing an example of a modified example of the cylinder-type gas generator according to the present embodiment. As shown in FIG. 5, in the cylinder-type gas generator 1A', a coil spring 80' different from the above-described coil spring 80 is used when compared with the above-described cylinder-type gas generator 1A.

[0101] That is, the coil spring 80' is configured such that the wire diameter of the metal wire is larger, the inner diameter is larger, and the number of turns is greater than those of the coil spring 80. Even with this configuration, the above-mentioned effects can be obtained.

[0102] In this way, design elements such as the wire diameter and number of turns of the metal wire constituting the coil spring can be changed as necessary, not limited to the inner diameter of the coil spring that determines the size of the clearance between the ignition part 41 and the surrounding part 81 described above. For example, the wire diameter of the metal wire is preferably made thinner from the viewpoint of facilitating the assembly work and reducing weight, and is preferably made thicker from the viewpoint of more firmly fixing the sealed container and increasing the directionality of the heat particles described above. In addition, the number of turns of the metal wire is preferably coarser from the viewpoint of reducing weight, and is preferably finer from the viewpoint of increasing the directionality of the heat particles described above. Furthermore, the material of the metal wire constituting the coil spring can also be changed in various ways.

[0103] (Embodiment 2) Fig. 6 is an enlarged cross-sectional view of the vicinity of the igniter of a cylinder-shaped gas generator according to Embodiment 2. Next, with reference to Fig. 6, a cylinder-shaped gas generator 1B according to the present embodiment will be described.

[0104] As shown in Fig. 6, when cylinder-shaped gas generator 1B according to the present embodiment is compared with cylinder-shaped gas generator 1A according to the first embodiment described above, the inner diameter of coil spring 80 is different, whereby surrounding portion 81 (see Fig. 4), which is the portion of coil spring 80 that surrounds ignition portion 41, is in contact with ignition portion 41. That is to say, in cylinder-shaped gas generator 1B according to the present embodiment, there is no clearance between ignition portion 41 and surrounding portion 81.

[0105] In this configuration, it is necessary to press the coil spring 80 into the ignition part 41 during assembly, and although this makes the workability slightly inferior to the case where a clearance is provided, it is possible to more reliably prevent the side wall part of the cup body 41c from cracking or deforming. Therefore, even when the configuration of this embodiment is adopted, it is possible to achieve both weight reduction and reduction in manufacturing costs while maintaining good gas output characteristics, as in the case of the above-mentioned first embodiment.

[0106] (Embodiment 3) Fig. 7 is an enlarged cross-sectional view of the vicinity of the igniter of a cylinder-shaped gas generator according to Embodiment 3. Next, with reference to Fig. 7, cylinder-shaped gas generator 1C according to the present embodiment will be described.

[0107] 7, cylinder-shaped gas generator 1C according to the present embodiment differs from cylinder-shaped gas generator 1A according to embodiment 1 described above in the shape of coil spring 80. Specifically, coil spring 80 has a reduced diameter portion (i.e., a portion with a relatively small inner diameter) in the axial central portion, and has expanded diameter portions (i.e., portions with a relatively large inner diameter) at both axial ends.

[0108] Here, of the reduced diameter portion and increased diameter portion of coil spring 80 described above, the reduced diameter portion and the increased diameter portion located on the holder 20 side are positioned so as to surround ignition portion 41 of igniter 40, and these portions correspond to the above-mentioned surrounding portion 81 (see FIG. 4). And, of coil spring 80, the reduced diameter portion surrounding ignition portion 41 of igniter 40 is press-fitted into ignition portion 41 so as to contact ignition portion 41. That is, in cylinder-shaped gas generator 1C according to the present embodiment, there is no clearance between ignition portion 41 and the reduced diameter portion of surrounding portion 81.

[0109] In this configuration, it is necessary to press the coil spring 80 into the ignition part 41 during assembly, and although this makes the workability slightly inferior to the case where a clearance is provided, it is possible to more reliably prevent the side wall part of the cup body 41c from cracking or deforming. Therefore, even when the configuration of this embodiment is adopted, it is possible to achieve both weight reduction and reduction in manufacturing costs while maintaining good gas output characteristics, as in the case of the above-mentioned first embodiment.

[0110] Furthermore, by providing enlarged diameter portions at both axial ends of the coil spring 80 as in this embodiment, the insertion direction of the coil spring 80 is not restricted during assembly, and the coil spring 80 can be more easily pressed into the ignition portion 41.

[0111] (Verification test) The following describes verification tests carried out to confirm the effects of the present invention. In the verification tests, cylinder-shaped gas generators according to Verification Examples 1 to 5 based on the above-mentioned embodiment 1 were actually prototyped, and separately, cylinder-shaped gas generators according to Comparative Examples 1 and 2 not based on the above-mentioned embodiment 1 were prototyped, and the gas output characteristics were measured by actually operating these cylinder-shaped gas generators according to Verification Examples 1 to 5 and Comparative Examples 1 and 2.

[0112] Fig. 8 is an enlarged cross-sectional view of the vicinity of the igniter of the cylinder-shaped gas generator according to Comparative Example 1. Also, Fig. 9 is a table showing the test conditions and test results of the verification test.

[0113] As shown in Fig. 9, none of the cylinder-shaped gas generators according to Verification Examples 1 to 5 are equipped with combustion control cover 43 (see Fig. 8) that is included in cylinder-shaped gas generator 1X according to Comparative Example 1 described below, and are configured so that the degree of opening of cup body 41c (see Fig. 2, etc.) of ignition portion 41 is regulated by coil spring 80. Here, in Verification Examples 1 to 5, the inner diameter, wire diameter and number of turns of coil spring 80 used are configured to be different, but the free length is configured to be the same.

[0114] On the other hand, as shown in Fig. 8, in cylinder-shaped gas generator 1X according to comparative example 1, a substantially cylindrical metallic combustion control cover 43 is extrapolated to ignition portion 41 of igniter 40. Combustion control cover 43 is for efficiently guiding thermal particles generated by igniter 40 during activation to gas generating agent 70. Combustion control cover 43 is fixed to holder 20 by crimping portion 23 provided on holder 20 together with igniter 40.

[0115] In cylinder-shaped gas generator 1X according to comparative example 1 configured in this manner, instead of coil spring 80 explained in the above-mentioned embodiment 1, combustion control cover 43 provides directionality to the thermal particles generated in ignition portion 41. For that reason, in cylinder-shaped gas generator 1X according to comparative example 1, coil spring 80″ is provided only for fixing sealed container 60 inside the housing, and coil spring 80″ does not regulate the degree to which cup body 41c of ignition portion 41 (see FIG. 2, etc.) is opened.

[0116] Furthermore, although not shown, the cylinder-shaped gas generator according to comparative example 2 is obtained by removing combustion control cover 43 from cylinder-shaped gas generator 1X according to comparative example 1 described above. Here, in cylinder-shaped gas generator 1X according to comparative example 2, coil spring 80" is positioned so as to face ignition portion 41, but since coil spring 80" is positioned significantly away from ignition portion 41, as will be clear from the test results described later, coil spring 80" does not restrict the degree to which cup body 41c of ignition portion 41 (see FIG. 2, etc.) is opened.

[0117] Here, the cylindrical gas generators according to Verification Examples 1 to 5 and Comparative Examples 1 and 2 were configured so that only the configurations of the coil spring and the combustion control cover differed from one another, and all other configurations were configured to be the same. The inner diameter R1 of the gas generating agent storage chamber S1A was 16.1 [mm] in all cases, the outer diameter R1 of the ignition portion 41 was 8.2 [mm] in all cases, the distance L1 along the axial direction of the housing body 10 from the portion of the ignition portion 41 in which the ignition charge 41a is accommodated to the gas generating agent storage chamber S1A was 11.1 [mm] in all cases, and the distance L2 along the axial direction of the housing body 10 from the portion of the ignition portion 41 in which the ignition charge 41a is accommodated to the sealed container 60 was 2.9 [mm] in all cases.

[0118] In the verification test, five samples each of the cylinder-type gas generators according to Verification Examples 1 to 5 and Comparative Examples 1 and 2 were prepared, each of which was placed in a sealed tank and activated, and the change in pressure inside the tank over time was measured. Note that the output index in Fig. 9 is used when evaluating the gas output characteristics, and indicates the time from the activation of the igniter until a change occurs in the pressure inside the tank.

[0119] As shown in Fig. 9, it was confirmed that the cylinder-shaped gas generators according to Verification Examples 1 to 4, in which the clearance C between the ignition portion and the surrounding portion is 1.0 [mm] or less, provide gas output characteristics equivalent to those of the cylinder-shaped gas generator according to Comparative Example 1, in which a combustion control cover is provided. In particular, it was confirmed that the cylinder-shaped gas generators according to Verification Examples 1 to 3 have improved output indexes compared to the cylinder-shaped gas generator according to Comparative Example 1, and provide gas output sooner after activation.

[0120] On the other hand, in the cylindrical gas generator of verification example 5, in which the clearance C between the ignition portion and the surrounding portion is 1.9 mm, gas output characteristics were only approximately equal to those of the cylindrical gas generator of comparison example 2, in which no combustion control cover was provided, and it was experimentally confirmed that the clearance C between the ignition portion and the surrounding portion is an important factor.

[0121] In FIG. 9, the evaluations of the cylindrical gas generators according to the above-mentioned verification examples 1 to 5 and comparative examples 1 and 2 in terms of manufacturing cost and gas output characteristics are expressed as “good” or “fair”, and an overall evaluation based on both of these evaluations is expressed as “excellent”, “good” or “fair”.

[0122] (Other forms, etc.) In the above-mentioned embodiment of the present invention and its modified examples, the coil spring for providing directionality to the heat particles generated in the ignition part of the igniter is described as being a coil spring having an overall cylindrical outer shape in which the metal wire is wound so as to have the same inner diameter at any position in the axial direction, or a coil spring configured so that the inner diameter varies in parts, but it is not necessary to use a coil spring with such an outer shape, and a coil spring configured to taper or expand as a whole may be used. In either case, as long as the coil spring is configured to regulate the degree of opening of the cup body of the ignition part, a corresponding effect can be obtained.

[0123] In the above-mentioned embodiment of the present invention and its modified examples, the case where one end of the coil spring is configured to abut against the crimped portion provided on the holder for fixing the igniter has been described as an example, but the one end of the coil spring may abut against a surface of the holder located outside the crimped portion. Also, as described above, the one end of the coil spring does not necessarily have to abut against the holder, and may be fixed only by being pressed into the ignition portion without abutting against it.

[0124] Furthermore, in the above-mentioned embodiment of the present invention and its modified examples, the present invention has been described as being applied to a cylindrical gas generator incorporated in a side airbag device, but the application of the present invention is not limited to this, and the present invention can also be applied to cylindrical gas generators incorporated in curtain airbag devices, knee airbag devices, seat cushion airbag devices, etc., and so-called T-shaped gas generators which have an elongated outer shape similar to a cylindrical gas generator.

[0125] As such, the above-mentioned embodiment and its modified examples disclosed herein are illustrative in all respects and are not restrictive. The technical scope of the present invention is defined by the claims, and includes all modifications within the meaning and scope equivalent to the description of the claims. [Explanation of symbols]

[0126] 1A, 1A', 1B, 1X Cylinder-type gas generator, 10 Housing body, 11 Gas outlet, 12, 13 Crimping portion, 20 Holder, 21 Penetration portion, 22 Annular groove portion, 23 Crimping portion, 24 Recess portion, 30 Closure member, 31 Annular groove portion, 40 Igniter, 41 Ignition portion, 41a Ignition charge, 41b Plug, 41c Cup body, 42 Terminal pin, 43 Combustion control cover, 50 Partition member, 51 Partition wall portion, 51a Score, 52 Annular wall portion, 60 Sealed container, 61 Container body, 61a Top wall portion, 61b Side wall portion, 61b1 Opening end, 62 Lid body, 62a Bottom portion, 62b Roll-up portion, 62b1 First crimping portion, 62b2 second crimping portion, 70 gas generating agent, 71 autoignition agent, 72 partition member, 72a positioning recess, 72b fixing cylindrical portion, 72c through hole, 73 spring-like member, 73a spring portion, 73b pressing portion, 80, 80', 80" coil spring, 81 surrounding portion, 82 extension portion, 90 filter, 91 hollow portion, S1 combustion chamber, S1A gas generating agent storage chamber, S1B heat insulating layer, S2 filter chamber.

Claims

1. a long cylindrical housing having a peripheral wall portion whose one axial end and the other axial end are closed; a gas generating charge disposed within the housing; an igniter having an ignition part containing an ignition charge for burning the gas generating agent, the ignition part being mounted on the one end part of the housing so as to be positioned so as to protrude toward the inside of the housing; a coil spring that is interposed between the one end of the housing and the gas generating agent, and that biases the gas generating agent toward the other end of the housing while separating the gas generating agent from the ignition portion, thereby fixing the gas generating agent inside the housing, The ignition portion includes a cup body that is cleaved by ignition of the ignition charge when the igniter is activated, a coil spring that is disposed approximately coaxially with an ignition portion and surrounds the ignition portion without any other member being interposed between the coil spring and the ignition portion, so that the degree of opening of the cup body when the cup body is torn open is regulated by the coil spring.

2. The ignition part has a generally cylindrical outer shape, 2. The gas generator according to claim 1, wherein the coil spring has an outer shape that is substantially cylindrical.

3. 3. The gas generator according to claim 1, wherein a surrounding portion which is a portion of said coil spring surrounding said ignition portion is not in contact with said ignition portion.

4. 3. The gas generator according to claim 1, wherein a surrounding portion which is a portion of said coil spring surrounding said ignition portion is in contact with said ignition portion.

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