Gas generator

Abstract

To provide a gas generator capable of efficiently guiding thermal particles produced in an igniter to a gas generating agent.SOLUTION: A gas generator 1 comprises: a cylindrical housing body 10 including therein a combustion chamber S1 where a gas generating agent 60 is accommodated; a holder 20 assembled to the housing body 10; an igniter 40 which includes an ignition part 42 including a squib cup loaded with an ignition charge, and which is held by the holder 20; and regulation means for regulating an opening degree of the squib cup when the squib cup is cleaved at the time of actuation of the igniter 40. The regulation means comprises a coil spring which has one end abutting on the holder 20 and / or the igniter 40 and has the other end abutting on the gas generating agent 60, and which is accommodated in the combustion chamber S1 so as to surround the ignition part 42 at an end part on a side of the holder 20.SELECTED DRAWING: Figure 2

Description

[Technical Field]

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

[0002] Airbag devices, which are passenger protection devices, have become widespread from the viewpoint of protecting passengers in automobiles, etc. Airbag devices are installed to protect passengers from impacts that occur during a vehicle collision, and the airbag instantly inflates and deploys during a vehicle collision, thereby acting as a cushion to support the passenger's body.

[0003] The gas generator is incorporated into this airbag device. When a vehicle crashes, the control unit energizes the igniter, which then generates a flame that burns the 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 specifications such as the installation position relative to a vehicle, output, etc. One of these is what is called a cylinder-type gas generator. A cylinder-type gas generator has an elongated 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 assembled to one axial end of the housing, and a combustion chamber containing a gas generating agent is provided on the one end side, and 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 the part that defines the filter chamber.

[0006] In a cylinder-shaped 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 through the gas outlet.

[0007] In general, it is important that the gas generating agent in a gas generator is sealed airtight 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 container made of a fragile material that melts or bursts due to the heat or pressure generated by activation of the igniter, and then seal the container and place it inside the housing.A cylinder-type gas generator employing this method is disclosed, for example, in JP 2018-69924 A (Patent Document 1).

[0009] However, when the above-mentioned method is adopted, there is a problem that the manufacturing cost is increased. That is, the container made of the above-mentioned fragile material has a relatively high component cost, and the operation of sealing the container after storing the gas generating agent in the container requires a considerable amount of work, which also increases the manufacturing cost.

[0010] On the other hand, in a cylinder-type gas generator, another method for preventing the gas generating agent from absorbing moisture is to provide, for example, O-rings or sealing tape in various locations on the housing so that the combustion chamber containing the gas generating agent is airtightly sealed. A cylinder-type gas generator employing this method is disclosed, for example, in Japanese Patent Laid-Open No. 2008-296763 (Patent Document 2).

[0011] In the cylinder-shaped gas generator disclosed in Patent Document 2, the housing is configured to include a substantially cylindrical housing main body and a holder that holds an igniter and is inserted into the open end of the housing main body, a sealing member such as an O-ring is interposed between the housing main body and the holder, and a sealing member such as sealing tape is affixed to close a communication hole provided in a member that separates the combustion chamber and the filter chamber, thereby ensuring airtightness in these parts. Furthermore, by employing such a method, manufacturing costs can be reduced compared to using a sealed container. [Prior art documents] [Patent documents]

[0012] [Patent Document 1] Japanese Patent Application Publication No. 2018-69924 [Patent Document 2] Japanese Patent Application Laid-Open No. 2008-296763 Summary of the Invention [Problem to be solved by the invention]

[0013] However, in the cylinder-type gas generator disclosed in Patent Document 2, the functions and characteristics of the holder described above require the holder to hold the igniter, accept a connector connected to the igniter, provide a strong connection with the housing body, and be strong enough to withstand the increase in internal pressure in the combustion chamber when the gas generator is activated. This inevitably results in a complex shape for the holder and requires high machining precision, resulting in the problem of high component costs for the holder.

[0014] Furthermore, since the holder is a relatively large metal part, there is also the problem that the weight of the cylinder-type gas generator inevitably increases.

[0015] SUMMARY OF THE INVENTION Accordingly, the present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a gas generator that is lighter in weight and has reduced manufacturing costs. [Means for solving the problem]

[0016] A gas generator according to the present invention includes a housing body, a holder assembly, and an igniter. The housing body is a cylindrical metal member that includes a combustion chamber therein that houses a gas generating agent. The holder assembly is inserted into the axial open end of the housing body and includes a through-hole-like hollow opening that extends parallel to the axial direction of the housing body. The igniter includes an ignition portion that houses an ignition charge and a terminal pin connected to the ignition portion, and at least a portion of the igniter is disposed inside the hollow opening with the ignition portion located on the combustion chamber side and the terminal pin located on the opposite side from the combustion chamber. The holder assembly includes a metal holder portion located on the combustion chamber side that receives and holds the igniter, and a resin connector portion located on the opposite side from the combustion chamber that can receive a connector connected to the terminal pin. The holder portion includes a cylindrical first barrel portion that defines the hollow opening and an annular protrusion that protrudes from the first barrel portion along the radial direction of the housing body. The connector portion includes a cylindrical second body portion that defines the hollow opening, and a cylindrical portion extending from the second body portion toward the combustion chamber. The cylindrical portion is inserted into the open end of the housing body, and is externally inserted into a portion of the first body portion that is located on the opposite side from the combustion chamber side as seen from the annular protrusion. In the gas generator based on the present invention, the diameter of the portion of the housing body corresponding to the cylindrical portion narrows radially inward, and therefore the cylindrical portion is sandwiched and compressed by the housing body and the first body portion at the narrowed diameter portion, whereby the cylindrical portion seals the gap between the housing body and the first body portion.

[0017] In the gas generator based on the present invention, the inner diameter of the cylindrical portion may be larger than the inner diameter of the second body, and the connector portion may be provided with an annular stepped surface connecting the inner circumferential surface of the second body and the inner circumferential surface of the cylindrical portion, thereby forming a first chamber defined by the annular stepped surface and the inner circumferential surface of the cylindrical portion at an axial end portion of the connector portion located on the combustion chamber side. In this case, it is preferable that the first body is inserted into the first chamber, and an axial end face of the first body located opposite the combustion chamber side abuts on the annular stepped surface.

[0018] In the gas generator based on the present invention, the inner diameter of the second barrel portion is larger than the inner diameter of the first barrel portion, so that a second chamber defined by the axial end face of the first barrel portion located opposite the combustion chamber side and an inner circumferential surface of the second barrel portion is provided at an axial end portion of the holder assembly located opposite the combustion chamber side. In this case, it is preferable that a receiving portion for a connector to be connected to the terminal pin is formed by the second chamber.

[0019] In the gas generator according to the present invention, the outer peripheral surface of the first body portion may have a diameter that decreases toward the combustion chamber.

[0020] The gas generator according to the present invention may further include a filter disposed inside the housing main body, and a partition member disposed inside the housing main body to divide the internal space of the housing main body in the axial direction of the housing main body into a filter chamber in which the filter is disposed and the combustion chamber. In this case, the partition member may be fixed to the housing main body by welding. [Effects of the Invention]

[0021] According to the present invention, a gas generator can be obtained that can be manufactured at reduced cost and with reduced weight. [Brief explanation of the drawings]

[0022] [Figure 1] 1 is a schematic view of a cylinder-shaped gas generator according to an embodiment. [Figure 2] 2 is an enlarged cross-sectional view of the vicinity of an igniter of the cylinder-shaped gas generator shown in FIG. 1. FIG. [Figure 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. FIG. [Figure 4] 1. FIG. 4 is a cross-sectional view showing a procedure for assembling a holder assembly in the cylinder-shaped gas generator shown in FIG. [Figure 5] 1. FIG. 4 is a cross-sectional view showing a procedure for assembling a holder assembly in the cylinder-shaped gas generator shown in FIG. [Figure 6] FIG. 10 is a cross-sectional view of a holder assembly of a cylinder-shaped gas generator according to first to fourth modified examples. DETAILED DESCRIPTION OF THE INVENTION

[0023] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The embodiments shown below exemplify the case where the present invention is applied to a cylinder-type gas generator incorporated in a side airbag device. In the embodiments shown below, the same or common parts are designated by the same reference numerals in the drawings, and their description will not be repeated.

[0024] Fig. 1 is a schematic diagram of a cylinder-shaped gas generator according to an embodiment. Figs. 2 and 3 are enlarged cross-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 1 according to the present embodiment will be described.

[0025] 1, cylinder-shaped gas generator 1 according to the present embodiment has an elongated cylindrical outer shape and includes a elongated cylindrical housing with one axial end and the other axial end closed. The housing includes housing main body 10, holder assembly 20, and closing member 30.

[0026] The housing, which is made up of the housing main body 10, the holder assembly 20, and the closing member 30, contains internal components such as an igniter 40, a partition member 50, a gas generating agent 60, a coil spring 70, and a filter 80. Also located inside the housing are a combustion chamber S1 in which the gas generating agent 60, one of the internal components described above, is mainly disposed, and a filter chamber S2 in which the filter 80 is disposed.

[0027] The housing body 10 forms the peripheral wall of the housing and is made of a long, cylindrical member with openings at both axial ends. The holder assembly 20 is made of a tubular member with a through-hole-like hollow opening extending parallel to the axial direction of the housing body 10, and has a holder portion 20A and a connector portion 20B, which will be described later. The closing member 30 has a cup shape including a closing portion 31 and a side wall portion 32, and the peripheral surface of the side wall portion 32 has an annular recess 33 for crimping, which will be described later. This annular recess 33 for crimping, is formed on the peripheral surface of the side wall portion 32 so as to extend circumferentially.

[0028] The housing body 10 may be made of a metal member such as stainless steel, iron steel, aluminum alloy, or stainless alloy, 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.

[0029] 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.

[0030] On the other hand, the holder portion 20A and the closing member 30 of the holder assembly 20 are made of metal members such as stainless steel, iron steel, aluminum alloy, stainless alloy, or the like.

[0031] The holder assembly 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 assembly 20 inserted into the one open end of the housing body 10, a predetermined position of the housing body 10 is reduced in diameter radially inward toward the outer circumferential surface of the holder assembly 20, thereby crimping and fixing the holder assembly 20 to the housing body 10. As a result, one axial end of the housing is formed by the holder assembly 20. Details of this crimping and fixing will be explained later.

[0032] The closing member 30 is fixed to the housing body 10 so as to close the other axial open end of the housing body 10. Specifically, with the closing member 30 inserted into the other open end of the housing body 10, a portion of the housing body 10 corresponding to an annular recess 33 provided on the circumferential surface of the side wall portion 32 of the closing member 30 is reduced in diameter radially inward to engage with the annular recess 33, thereby crimping and fixing the closing member 30 to the housing body 10. In this way, the other axial end of the housing is defined by the closing member 30.

[0033] These crimping methods are called eight-way crimping, which reduces the diameter of the housing body 10 radially inward in a substantially uniform manner. By performing this eight-way crimping, crimped portions 12 and 13 are formed on the housing body 10. As a result, the crimped portions 12 and 13 come into direct contact with the outer circumferential surface of the holder assembly 20 and the annular recess 33, respectively, preventing a gap from forming between them.

[0034] The assembly structure of the closing member 30 to the housing main body 10 is not limited to the above-described assembly structure, and other assembly structures may be adopted. Furthermore, the housing main body 10 and the closing member 30 may not be separate bodies, but may be configured as a single member having a cylindrical shape with a bottom.

[0035] 1 and 2, the igniter 40 is mounted to the one axial end of the housing by being supported by the holder assembly 20. The igniter 40 is used to combust the gas generating agent 60, and is installed so as to face the interior space of the housing.

[0036] Igniter 40 is used to generate a flame and is also called a squib. Igniter 40 includes a base 41, an ignition unit 42, and a pair of terminal pins 43. Base 41 is a portion that holds ignition unit 42 and the pair of terminal pins 43, and is also a portion that is fixed to holder assembly 20. Base 41 holds the pair of terminal pins 43 by inserting them therethrough.

[0037] Ignition unit 42 contains an ignition charge that ignites and burns to generate a flame when activated, and a resistor (bridge wire) for igniting the ignition charge. A pair of terminal pins 43 are connected to ignition unit 42 to ignite the ignition charge.

[0038] More specifically, ignition unit 42 includes a squib cup formed in a cup shape, the resistor described above is attached so as to connect the tips of a pair of terminal pins 43 inserted into this squib cup, and an ignition charge is loaded in the squib cup so as to surround or be close to this resistor. Furthermore, ignition unit 42 may be loaded with an enhancer charge as needed.

[0039] Here, the resistor typically uses nichrome wire or resistance wire made of an alloy containing platinum and tungsten, and the ignition charge typically uses ZPP (zirconium-potassium perchlorate), ZWPP (zirconium-tungsten-potassium perchlorate), lead tricinate, etc. Furthermore, the transfer charge typically uses a composition consisting of a metal powder / oxidizer, such as B / KNO3, B / NaNO3, or Sr(NO3)2, a composition consisting of titanium hydride / potassium perchlorate, or a composition consisting of B / 5-aminotetrazole / potassium nitrate / molybdenum trioxide.

[0040] When a collision is detected, a predetermined amount of current flows through the resistor via the terminal pin 43. This current flow generates Joule heat in the resistor, causing the ignition charge to begin burning. The high-temperature particles generated by the combustion split open the squib cup containing the ignition charge. The time from when the current flows through the resistor to when the igniter 40 is activated is generally 2 milliseconds or less when nichrome wire is used for the resistor.

[0041] Igniter 40 is fixed to holder assembly 20 with its ignition portion 42 positioned to protrude into the housing and with a portion of it disposed inside the hollow opening of holder assembly 20. As a result, igniter 40 has its ignition portion 42 positioned on the combustion chamber S1 side and its terminal pin 43 positioned on the opposite side from combustion chamber S1. Details of the fixing structure of igniter 40 to holder assembly 20 will be explained later.

[0042] 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.

[0043] 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, or stainless alloy. 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 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 80, and the outer peripheral surface of the annular wall portion 52 abuts against the inner peripheral surface of the housing body 10.

[0044] Scores 51a are provided on the main surface of the partition wall portion 51 that contacts the filter 80. The scores 51a are intended to cause the partition wall portion 51 to break and form openings as the internal pressure of the combustion chamber S1 increases due to combustion of the gas generating agent 60, and are configured, for example, by a plurality of grooves that are provided radially so as to intersect with one another. The scores 51a are provided in a portion of the filter 80 that faces the hollow portion 81.

[0045] The partition member 50 is fixed by being inserted into the housing main body 10 and joined to the housing main body 10. More specifically, the partition member 50 is press-fitted into the housing main body 10 and fixed by welding the annular wall portion 52 of the partition member 50 to the housing main body 10 at or near the contact portion between them.

[0046] As a result, a welded portion 90 extending along the circumferential direction of the housing main body 10 is formed in the housing main body 10 and the partition member 50 corresponding to the portion into which the partition member 50 is inserted. Note that electron beam welding, laser welding, resistance welding, etc. can be suitably used to weld the partition member 50 and the housing main body 10 together.

[0047] When the partition member 50 is fixed to the housing main body 10 by welding in this manner, the gap between the partition member 50 and the housing main body 10 is filled with the welded portion 90, thereby sealing the gap. Therefore, with this configuration, it is possible to ensure airtightness in that portion.

[0048] The method of fixing the partition member 50 to the housing main body 10 is not limited to the above-mentioned methods using press-fitting and welding, and other fixing methods may be used. In such cases, airtightness between the partition member 50 and the housing main body 10 can be ensured by providing an O-ring, sealing tape, or the like in an appropriate position.

[0049] As shown in FIGS. 1 to 3, within the space inside the housing, a gas generating agent 60 and a coil spring 70 are arranged in the space sandwiched between the holder assembly 20 and the partition member 50 (i.e., the combustion chamber S1).

[0050] The gas generating agent 60 is an agent that generates gas by being ignited and burning by thermal particles generated by the activation of the igniter 40. A non-azide gas generating agent is preferably used as the gas generating agent 60, and the gas generating agent 60 is generally configured as a molded body containing fuel, an oxidizer, and an additive.

[0051] The fuel may be, for example, a triazole derivative, a tetrazole derivative, a guanidine derivative, an azodicarbonamide derivative, a hydrazine derivative, or a combination thereof. Specifically, nitroguanidine, guanidine nitrate, cyanoguanidine, 5-aminotetrazole, or the like is preferably used.

[0052] Examples of oxidizing agents include basic metal salts such as basic copper nitrate and basic copper carbonate, perchlorates such as ammonium perchlorate and potassium perchlorate, and nitrates containing cations selected from alkali metals, alkaline earth metals, transition metals, and ammonia. Suitable nitrates include sodium nitrate and potassium nitrate.

[0053] Examples of additives include binders, slag formers, and combustion adjusters. Suitable binders include organic binders such as metal salts of carboxymethyl cellulose and stearates, and inorganic binders such as synthetic hydrotalcite and acid clay. Suitable slag formers include silicon nitride, silica, and acid clay. Suitable combustion adjusters include metal oxides, ferrosilicon, activated carbon, and graphite.

[0054] The shape of the molded body of the gas generating agent 60 may be various, including granular, pellet-like, cylindrical, or other granular shapes, as well as disk-like shapes. Furthermore, 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) are also used. These shapes are preferably selected appropriately depending on the specifications of the airbag device into which the cylindrical gas generator 1 is to be incorporated. It is preferable to select an optimal shape depending on the specifications, such as a shape in which the rate of gas generation changes over time when the gas generating agent 60 burns. Furthermore, in addition to the shape of the gas generating agent 60, it is preferable to select the size and filling amount of the molded body appropriately, taking into consideration the linear burning velocity, pressure exponent, etc. of the gas generating agent 60.

[0055] The coil spring 70 is provided for the purpose of preventing the gas generating agent 60, which is a molded body, from being crushed by vibration or the like, and has a spring portion 71 and a pressing portion 72 formed by bending a metal wire. One end of the spring portion 71 is disposed so as to abut against the holder assembly 20 and / or the igniter 40, and the pressing portion 72 is formed at the other end. The pressing portion 72 is formed, for example, by arranging metal wires in approximately parallel relation at a predetermined interval, and abuts against the gas generating agent 60.

[0056] As a result, the gas generating agent 60 is elastically biased by the coil spring 70 toward the partition member 50 side, and is prevented from moving inside the housing.

[0057] Here, the end of coil spring 70 on the holder assembly 20 side surrounds ignition portion 42 of igniter 40 so as to be in contact with ignition portion 42 of igniter 40 or so as to be positioned close to ignition portion 42 of igniter 40 with a predetermined clearance. With this configuration, when the squib cup of ignition portion 42 breaks open upon activation of igniter 40, the degree to which the squib cup opens is restricted by coil spring 70.

[0058] Therefore, by appropriately regulating the degree of opening of the squib cup, the traveling direction of the thermal particles generated in the ignition part 42 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 60. In other words, the coil spring 70 surrounding the ignition part 42 also has the function of imparting directionality to the traveling direction of the thermal particles generated in the ignition part 42.

[0059] 1, within the space inside the housing, a filter 80 is disposed in the space sandwiched between the closing member 30 and the partition member 50 (i.e., the filter chamber S2). The filter 80 is made of a cylindrical member having a hollow portion 81 extending along a direction parallel to the axial direction of the housing body 10. One end face in the axial direction of the filter 80 abuts against the side wall portion 32 of the closing member 30, and the other end face in the axial direction abuts against the partition wall portion 51 of the partition member 50.

[0060] The filter 80 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 60 as the gas passes through the filter 80, and also functions as a removal means for removing slag (residue) and the like contained in the gas. As described above, by using the filter 80 made of a cylindrical member, the flow resistance to the gas flowing through the filter chamber S2 during operation is kept low, making it possible to achieve an efficient gas flow.

[0061] The filter 80 can be preferably made of an assembly of metal wire or metal mesh material made of stainless steel, iron, etc. Specifically, it can be made of a knitted wire mesh, a plain woven wire mesh, an assembly of crimped woven metal wire, or any of these compressed by a press.

[0062] A wound perforated metal plate or the like can also be used as the filter 80. In this case, examples of the perforated metal plate that can be used include expanded metal, which is made by cutting staggered slits in a metal plate and expanding the slits to form holes and process it into a mesh-like shape, and hook metal, which is made by drilling holes in a metal plate and flattening the burrs that form around the holes by crushing them.

[0063] The housing body 10 in the portion defining 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 used to guide the gas that has passed through the filter 80 to the outside of the housing.

[0064] Next, with reference to FIG. 1, an operation during operation of cylinder-shaped gas generator 1 according to the present embodiment will be described.

[0065] Referring to FIG. 1, when a vehicle equipped with cylinder-shaped gas generator 1 according to this embodiment collides, the collision is detected by collision detection means provided separately in the vehicle, and based on this, igniter 40 is activated by current supplied from a control unit provided separately in the vehicle.

[0066] When the igniter 40 is activated, the pressure inside the ignition section 42 increases due to the combustion of the ignition charge and / or the transfer charge, causing the squib cup of the ignition section 42 to burst, and the hot particles generated by the combustion of the ignition charge and / or the transfer charge to flow out of the ignition section 42.

[0067] The thermal particles flowing out from the ignition part 42 are given directionality by the above-mentioned coil spring 70, and as a result reach the gas generating agent 60 contained in the combustion chamber S1. The thermal particles that reach the gas generating agent 60 combust the gas generating agent 60, thereby generating a large amount of gas in the combustion chamber S1.

[0068] As a result, the pressure in the combustion chamber S1 increases, and when the internal pressure of the combustion chamber S1 reaches a predetermined pressure, a rupture occurs in the portion of the partition member 50 where the score 51a is provided. As a result, an opening is formed in the partition member 50 at the portion facing the hollow portion 81 of the filter 80, and the combustion chamber S1 and the filter chamber S2 are in communication with each other via the opening.

[0069] As a result, gas generated in the combustion chamber S1 flows into the filter chamber S2 through the opening formed in the partition member 50. The gas that has flowed into the filter chamber S2 flows axially through the hollow portion 81 of the filter 80, then changes direction toward the radial direction, and flows through the interior of the filter 80. During this process, the filter 80 removes heat and cools the gas, and the filter 80 also removes slag contained in the gas.

[0070] Then, the gas that has passed through filter 80 is ejected to the outside of the housing through gas outlet 11 provided in housing main body 10. The ejected gas is introduced into the inside of an airbag provided adjacent to cylinder-shaped gas generator 1, and inflates and deploys the airbag.

[0071] As described above, cylinder-shaped gas generator 1 according to the present embodiment has holder assembly 20 as part of the housing, and holder assembly 20 is attached to the open end on the one end side described above of housing main body 10. The configuration of holder assembly 20, the structure for fixing igniter 40 to holder assembly 20, and the structure for fixing holder assembly 20 to housing main body 10 will be described in detail below with reference to FIG. 2.

[0072] 2, the holder assembly 20 has a metal holder portion 20A located on the combustion chamber S1 side and a resin connector portion 20B located on the opposite side from the combustion chamber S1 side. The holder assembly 20 is configured as an integrated part by previously assembling the holder portion 20A and the connector portion 20B to each other, and this is attached to the opening on the one end side of the housing main body 10.

[0073] The holder portion 20A is composed of a flat, approximately disk-shaped member having a through portion extending axially in its center, and includes a cylindrical first body portion 21 and an annular protrusion 22 protruding outward from the outer peripheral surface of the first body portion 21.

[0074] The holder portion 20A is inserted into the housing body 10 so that its axial direction is parallel to the axial direction of the housing body 10. As a result, the through portion provided in the holder portion 20A defines a part of the hollow opening of the holder assembly 20, and the annular protrusion 22 protrudes from the first body portion 21 along the radial direction of the housing body 10. The annular protrusion 22 is provided at the end of the first body portion 21 on the combustion chamber S1 side.

[0075] Holder portion 20A defines combustion chamber S1 provided inside housing body 10, and is a member that functions as a pressure bulkhead. Therefore, holder portion 20A is made of a metal member as described above so that it has sufficient strength to withstand the increase in internal pressure in combustion chamber S1 when cylinder-shaped gas generator 1 is activated.

[0076] Holder portion 20A also serves as a member for receiving and holding igniter 40, and has a recessed accommodation portion 23a at its axial end on the combustion chamber S1 side to receive igniter 40. Accommodation portion 23a communicates with a through-hole provided in holder portion 20A. Furthermore, a crimping portion 23b is provided at the end of holder portion 20A on the combustion chamber S1 side, surrounding accommodation portion 23a. Crimping portion 23b is a portion for crimping and fixing igniter 40 to holder portion 20A.

[0077] Igniter 40 is fixed to holder part 20A with its base 41 accommodated in accommodation portion 23a of holder part 20A. Specifically, base 41 is inserted into accommodation portion 23a of holder part 20A, and base 41 is fastened against the bottom surface of accommodation portion 23a. In this state, crimping portion 23b provided on holder part 20A is bent, thereby fixing igniter 40 to holder part 20A. In this way, igniter 40 is held by holder part 20A.

[0078] Here, a seal member 29 made of an O-ring or the like is interposed between holder portion 20A and igniter 40, and thereby the gap between holder portion 20A and igniter 40 is filled with seal member 29, thereby sealing the gap. Therefore, with this configuration, it is possible to ensure airtightness in that portion. Note that the method of fixing igniter 40 is not limited to the fixing method using crimping portion 23b described above, and other fixing methods may also be used.

[0079] The connector portion 20B is composed of an approximately cylindrical member having a through portion extending axially in its center, and includes a cylindrical second body portion 24, a cylindrical portion 25 extending from one axial end of the second body portion 24 along the axial direction, and a flange portion 26 provided at the other axial end of the second body portion 24.

[0080] A portion of connector portion 20B is inserted into housing body 10 so that its axial direction is parallel to the axial direction of housing body 10. More specifically, a portion of connector portion 20B excluding flange portion 26 is inserted into the open end of housing body 10, and flange portion 26 abuts on the axial end face of housing body 10 outside of housing body 10. As a result, the through portion provided in connector portion 20B defines a portion of the hollow opening of holder assembly 20, and tubular portion 25 extends from second body portion 24 toward combustion chamber S1.

[0081] Here, the holder portion 20A is fixed by being press-fitted into the connector portion 20B. More specifically, the first body portion 21 of the holder portion 20A is press-fitted into the tubular portion 25 of the connector portion 20B, and this brings the first body portion 21 and the tubular portion 25 into pressure contact, thereby fixing the holder portion 20A and the connector portion 20B so that they do not easily come apart.

[0082] Connector portion 20B is for receiving a connection connector that is connected to terminal pin 43 of igniter 40. Terminal pin 43 of igniter 40 is arranged inside this connector portion 20B. The through portion provided in connector portion 20B described above constitutes a portion for receiving this connection connector.

[0083] More specifically, in cylinder-shaped gas generator 1, igniter 40 must be electrically connected to an externally provided control unit (not shown) of a vehicle or the like, and a harness is normally used for this electrical connection. A male connector is attached to the tip of this harness, and connector portion 20B must be provided with a female connector that can be connected to this male connector. The penetration portion provided in connector portion 20B constitutes this female connector.

[0084] Furthermore, when the male connector of the harness is inserted into the penetration portion that functions as a female connector, electrical continuity is established between the core wire of the harness and the terminal pin 43, thereby connecting the igniter 40 to a control unit of a vehicle, etc.

[0085] Connector portion 20B also functions as a member that ensures airtightness between housing main body 10 and holder portion 20A. The portion that ensures airtightness between housing main body 10 and holder portion 20A is mainly tubular portion 25 of connector portion 20B.

[0086] Specifically, the cylindrical portion 25 is inserted into the open end of the housing body 10 and is also inserted onto the first body 21 of the holder portion 20A. As a result, in the portion of the housing body 10 where the cylindrical portion 25 is located in the axial direction, the first body 21 of the holder portion 20A, the cylindrical portion 25 of the connector portion 20B, and the housing body 10 are arranged in this order from the radially inner side to the radially outer side of the housing body 10. In other words, the first body 21 is surrounded by the cylindrical portion 25, and the cylindrical portion 25 is surrounded by the housing body 10.

[0087] A crimped portion 12 that narrows radially inward is provided on the portion of housing body 10 that corresponds to cylindrical portion 25 (i.e., the portion that covers cylindrical portion 25). By providing this crimped portion 12, cylindrical portion 25 of connector portion 20B, which is made of a resin member, is sandwiched between crimped portion 12 of housing body 10, which is made of a metal member, and first body portion 21 of holder portion 20A, which is made of a metal member, and thereby the gap between housing body 10 and first body portion 21 is sealed by cylindrical portion 25.

[0088] When the crimping portion 12 is provided on the housing main body 10, the tubular portion 25 is sandwiched between the housing main body 10 and the first body portion 21, and the load causes compressive deformation in the tubular portion 25. As a result, the tubular portion 25 and the housing main body 10 come into close contact with each other, and the tubular portion 25 and the first body portion 21 come into close contact with each other.

[0089] Therefore, the cylindrical portion 25 is interposed between the housing main body 10 and the first body portion 21 while being in close contact with each of the housing main body 10 and the first body portion 21, thereby sealing the gap described above. Therefore, by configuring in this way, it is possible to ensure airtightness in that portion.

[0090] The material of the connector portion 20B is not particularly limited, but nylon-based resins such as nylon 6, nylon 66, and those filled with glass filler, polyacetal (POM) resin, polycarbonate (PC) resin, polyphenylene sulfide (PPS) resin, polybutylene terephthalate (PBT) resin, etc. can be suitably used.

[0091] In holder portion 20A, annular protrusion 22 is provided at a position closer to combustion chamber S1 than first body portion 21. Therefore, annular protrusion 22 also functions as a stopper that prevents holder assembly 20 from falling off from housing main body 10. This function of annular protrusion 22 as a stopper is exerted not only during manufacture of cylinder-shaped gas generator 1 and when it is not in operation, but also when it is subjected to pressure associated with an increase in the internal pressure of combustion chamber S1 during operation.

[0092] Here, in cylinder-shaped gas generator 1 according to the present embodiment, inner diameter R1 of tubular portion 25 is larger than inner diameter R2 of second body portion 24, and connector portion 20B is provided with annular step surface 27 that connects inner circumferential surface 24a of second body portion 24 and inner circumferential surface 25a of tubular portion 25. As a result, first chamber 28a defined by annular step surface 27 and inner circumferential surface 25a of tubular portion 25 is provided at the axial end of connector portion 20B located on the combustion chamber S1 side.

[0093] The first body portion 21 of the holder portion 20A is inserted into this first chamber 28a, and the axial end face 21a of the first body portion 21 located on the opposite side from the combustion chamber S1 abuts against the annular step surface 27.

[0094] By configuring it in this manner, the holder portion 20A and the connector portion 20B can be fixed together by pressing the holder portion 20A into the connector portion 20B, as described above, and the holder portion 20A and the connector portion 20B can be positioned accurately along the axial direction of the housing main body 10.

[0095] Furthermore, in cylinder-shaped gas generator 1 according to the present embodiment, inner diameter R2 of second barrel portion 24 is larger than inner diameter R3 of first barrel portion 21. As a result, second chamber 28b defined by axial end surface 21a of first barrel portion 21 located opposite to combustion chamber S1 and inner circumferential surface 24a of second barrel portion 24 is provided at the axial end portion located opposite to combustion chamber S1 of holder assembly 20.

[0096] This second chamber 28b corresponds to the through-hole provided in the connector portion 20B described above, and constitutes the female connector described above to be provided in the connector portion 20B.

[0097] By configuring it in this way, the above-mentioned female connector to be provided on the connector portion 20B can be easily provided on the connector portion 20B, and the configuration of the holder assembly 20 can be further simplified.

[0098] Figures 4 and 5 are cross-sectional views showing a procedure for assembling a holder assembly in the cylinder-shaped gas generator shown in Figure 1. Next, with reference to Figures 4 and 5, a procedure for assembling holder assembly 20 in cylinder-shaped gas generator 1 according to the present embodiment will be described.

[0099] When assembling holder assembly 20 to housing main body 10, first, as shown in Fig. 4, holder portion 20A to which igniter 40 is assembled is prepared, and this is then assembled to connector portion 20B. Specifically, first body portion 21 of holder portion 20A is press-fitted into cylindrical portion 25 of connector portion 20B, whereby holder portion 20A to which igniter 40 is assembled is assembled to connector portion 20B.

[0100] Next, the housing body 10 is fitted onto the holder assembly 20 in which the holder portion 20A is assembled to the connector portion 20B. At this time, the open end of the housing body 10 is fitted onto the holder assembly 20 so as to cover the second body portion of the connector portion 20B, and further, the axial end face of the housing body 10 is made to abut against the flange portion 26 of the connector portion 20B.

[0101] At this time, the holder portion 20A may be press-fitted into the housing main body 10. That is, the housing main body 10 may be fitted onto the holder assembly 20 so that the circumferential surface of the annular protrusion 22 of the holder portion 20A is in pressure contact with the inner circumferential surface of the housing main body 10. With this configuration, the housing main body 10 and the holder assembly 20 are temporarily fixed by this press-fitting, which makes subsequent handling easier.

[0102] Next, as shown in Fig. 5, a crimping process is performed to reduce the diameter of a predetermined position of the housing body 10. More specifically, the diameter of the portion of the housing body 10 corresponding to the cylindrical portion 25 of the connector portion 20B is reduced radially inward (i.e., in the direction of arrow A in the figure), thereby providing the crimped portion 12 on the housing body 10.

[0103] As a result, the tubular portion 25 of the connector portion 20B is sandwiched between the crimping portion 12 of the housing main body 10 and the first body portion 21 of the holder portion 20A, and the gap between the housing main body 10 and the first body portion 21 is sealed by the tubular portion 25.

[0104] By going through the above-described series of steps, the assembly of the holder assembly 20 to the housing main body 10 is completed, and the open end on the above-described one end side of the housing main body 10 is closed by the holder assembly 20.

[0105] By configuring the cylinder-shaped gas generator according to the present embodiment as described above, the gap between housing body 10 and holder assembly 20 can be sealed by tubular portion 25 of resin connector portion 20B, which is part of holder assembly 20. This eliminates the need to use a separate sealing member such as an O-ring to seal this portion, making it possible to reduce parts costs and greatly facilitating the assembly work.

[0106] Furthermore, by configuring a holder that was conventionally configured as a single metal part as a composite part consisting of a metal holder portion 20A and a resin connector portion 20B, the amount of metal material used can be dramatically reduced, resulting in a significant weight reduction. In addition, the high processing precision required when configuring a holder from a single metal part is no longer necessary, and the holder configuration is greatly simplified, which also makes it possible to reduce material costs and processing costs.

[0107] Therefore, by using cylinder-shaped gas generator 1 according to the present embodiment, it is possible to reduce the manufacturing cost and the weight compared to conventional gas generators.

[0108] Fig. 6 is a cross-sectional view of a holder assembly for a cylinder-shaped gas generator according to first to fourth modified examples based on the above-described embodiment. Holder assembly 20 for cylinder-shaped gas generators 1A to 1D according to the first to fourth modified examples will now be described with reference to Fig. 6.

[0109] Holder assembly 20 of cylinder-shaped gas generator 1A according to a first modified example shown in FIG. 6(A) differs from the embodiment described above only in the shape of first barrel portion 21 of holder portion 20A.

[0110] Specifically, in holder assembly 20 according to the first modification, outer peripheral surface 21b of first body portion 21 has an inclined shape in which the diameter decreases toward combustion chamber S1 (i.e., the side opposite connector portion 20B). Therefore, before holder assembly 20 is assembled to housing main body 10, a gap is generated between tubular portion 25 of connector portion 20B and first body portion 21 of holder portion 20A.

[0111] In this configuration, when crimping portion 12 is provided to housing body 10, tubular portion 25 of connector portion 20B is subjected to a load and compressively deformed while tilting radially inward of housing body 10. At this time, the load applied to first body portion 21 of holder portion 20A by crimping portion 12 provided to housing body 10 acts toward the side where terminal pin 43 of igniter 40 is located.

[0112] Therefore, when this configuration is adopted, the fixing force of the crimping portion 12 is applied more firmly to the holder portion 20A, and in addition to the effects described in the above-mentioned embodiment, the effect of more reliably preventing the holder assembly 20 from falling off the housing main body 10 can be obtained.

[0113] Holder assemblies 20 of cylinder-shaped gas generators 1B to 1D according to second to fourth modified examples shown in Figures 6(B) to 6(D) differ from the above-described embodiments only in the shape of cylindrical portion 25 of connector portion 20B.

[0114] Specifically, in the holder assemblies 20 relating to the second to fourth modified examples, a concave portion is pre-formed on the outer surface of the cylindrical portion 25 at a position corresponding to the crimping portion 12 provided on the housing main body 10.

[0115] Here, in the holder assembly 20 relating to the second modified example shown in Figure 6(B), the concave portion is configured to have a C-shaped cross section, and in the holder assembly 20 relating to the third modified example shown in Figure 6(C), the thin-walled portion formed in the tubular portion 25 by providing the concave portion is configured to extend from a position corresponding to the crimping portion 12 provided on the housing main body 10 toward the combustion chamber S1 side (i.e., the side opposite the flange portion 26 of the connector portion 20B), and in the holder assembly 20 relating to the fourth modified example shown in Figure 6(D), the thin-walled portion formed in the tubular portion 25 by providing the concave portion is configured to extend from a position corresponding to the crimping portion 12 provided on the housing main body 10 toward the side opposite the combustion chamber S1 side (i.e., the side opposite the flange portion 26 of the connector portion 20B).

[0116] In this configuration, when the crimping portion 12 is provided on the housing body 10, the adhesion between the crimping portion 12 of the housing body 10 and the tubular portion 25 of the connector portion 20B is improved.

[0117] Therefore, when this configuration is adopted, in addition to the effects described in the above embodiment, it is possible to improve the sealing performance between the housing body 10 and the first body portion 21.

[0118] The characteristic configurations shown in the above-described embodiments of the present invention and the modifications thereof can naturally be combined with each other within the scope of the gist of the present invention.

[0119] Furthermore, in the above-described embodiment and modified examples of the present invention, the application of the present invention to a cylinder-type gas generator incorporated in a side airbag device has been described as an example, but the application of the present invention is not limited to this, and the present invention can also be applied to cylinder-type 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 cylinder-type gas generator.

[0120] As such, the above-described embodiments and their modifications disclosed herein are illustrative in all respects and are not limiting. The technical scope of the present invention is defined by the claims, and includes all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0121] REFERENCE SIGNS LIST 1, 1A to 1D Cylinder-shaped gas generator, 10 Housing body, 11 Gas outlet, 12, 13 Crimping portion, 20 Holder assembly, 20A Holder portion, 20B Connector portion, 21 First body portion, 21a Axial end face, 21b Outer circumferential surface, 22 Annular protrusion portion, 23a Storage portion, 23b Crimping portion, 24 Second body portion, 24a Inner circumferential surface, 25 Cylindrical portion, 25a Inner circumferential surface, 26 Flange portion, 27 Annular stepped surface, 28a First chamber, 28b Second chamber, 29 Sealing member, 30 Closing member, 31 Closing portion, 32 Side wall portion, 33 Annular recess, 40 Igniter, 41 Base portion, 42 Ignition portion, 43 Terminal pin, 50 Partition member, 51 Partition wall portion, 51a Score, 52 Annular wall portion, 60 gas generating agent, 70 coil spring, 71 spring portion, 72 pressing portion, 80 filter, 81 hollow portion, 90 welding portion, S1 combustion chamber, S2 filter chamber.

Claims

1. a cylindrical housing body including a combustion chamber in which a gas generating agent is accommodated; a holder attached to an axial opening end of the housing body; an igniter having an ignition unit including a squib cup loaded with an ignition charge and a terminal pin connected to the ignition unit, the ignition unit being held by the holder in a state where the ignition unit is located on the combustion chamber side and the terminal pin is located on the opposite side from the combustion chamber side; a restricting means for restricting the degree of opening of the squib cup when the squib cup is torn open upon activation of the igniter, a restricting means configured by a coil spring housed in the combustion chamber, one end of which abuts against the holder and / or the igniter and the other end of which abuts against the gas generating agent, and which surrounds the ignition portion at the end on the holder side;

2. 2. The gas generator according to claim 1, wherein an end of said coil spring on said holder side is in contact with said ignition portion or is disposed close to said ignition portion with a predetermined clearance therebetween.

3. The coil spring in the portion surrounding the ignition part is cylindrical, 2. The gas generator according to claim 1, wherein the coil spring has a diameter that increases with increasing distance from the ignition portion along the axial direction of the housing body.

4. 2. The gas generator according to claim 1, wherein the coil spring elastically biases the gas generating agent in a direction opposite to the igniter side.

5. 5. The gas generator according to claim 4, wherein the other end of the coil spring is provided with a pressing portion that presses the gas generating agent.

6. The housing body is made of metal, the holder includes a through-hole-shaped hollow opening extending in a direction parallel to the axial direction of the housing body, and is assembled to the open end of the housing body by being inserted into the open end, the igniter is at least partially disposed within the hollow opening; the holder comprises a holder assembly including: a metal holder portion located on the combustion chamber side and configured to receive and hold the igniter; and a resin connector portion located on the opposite side from the combustion chamber side and configured to receive a connector to be connected to the terminal pin, the holder portion includes a cylindrical first body portion that defines the hollow opening, and an annular protrusion that protrudes from the first body portion along a radial direction of the housing main body, the connector portion includes a cylindrical second body portion that defines the hollow opening, and a cylindrical portion that extends from the second body portion toward the combustion chamber, the cylindrical portion is inserted into the open end of the housing body and is inserted around the first body portion at a portion thereof located on the opposite side from the combustion chamber side as viewed from the annular protrusion, 6. The gas generator according to claim 1, wherein a portion of the housing body corresponding to the cylindrical portion is tapered radially inward, whereby the cylindrical portion is sandwiched and compressed by the housing body at the tapered portion and the first barrel portion, whereby a gap between the housing body and the first barrel portion is sealed by the cylindrical portion.

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