JP7553389B2 - Gas generator - Google Patents

Description

The present invention relates to a gas generator that is incorporated into an airbag device as a passenger protection device equipped in an automobile or the like, and in particular to a so-called cylinder-type gas generator with a long cylindrical outer shape that is suitable for incorporation into a side airbag device or the like.

Conventionally, airbag devices, which are occupant protection devices, have become widespread from the viewpoint of protecting occupants of automobiles and the like. Airbag devices are installed in order to protect occupants from the impact that occurs when a vehicle or the like crashes, and the airbag instantly inflates and deploys when the vehicle or the like crashes, so that the airbag acts as a cushion to receive the occupant's body.

The gas generator is a device that is built into the airbag device. When a vehicle crashes, the control unit applies electricity to ignite an igniter, which then burns the gas generating agent with a flame, instantly generating a large amount of gas, causing the airbag to inflate and deploy.

There are gas generators with various configurations based on the specifications such as the installation position relative to the vehicle and the output. One of these is called a cylinder-type gas generator. A cylinder-type gas generator has a long cylindrical outer shape and is suitable for incorporation into side airbag devices, curtain airbag devices, knee airbag devices, seat cushion airbag devices, etc.

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

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 that has passed through the filter is ejected to the outside through the gas ejection port.

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

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 the activation of the igniter, seal the container, and then place it inside the housing. A cylinder-type gas generator that employs this method is disclosed, for example, in JP 2018-69924 A (Patent Document 1).

However, when the above method is adopted, there is a problem that the manufacturing costs are put under pressure. That is, the container made of the above-mentioned fragile material has a relatively high component cost, and the task of sealing the container after placing the gas generating agent in it requires a considerable amount of work, which also increases the manufacturing costs.

On the other hand, another method for preventing the gas generating agent from absorbing moisture in a cylinder-type gas generator is to provide O-rings or sealing tape, for example, in various places in 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 JP 2008-296763 A (Patent Document 2).

In the cylinder-type gas generator disclosed in Patent Document 2, the housing is configured to include a substantially cylindrical housing body and a holder that holds an igniter and is inserted into the open end of the housing body, with a sealing member, such as an O-ring, interposed between the housing body and the holder, and a sealing member, such as sealing tape, attached to close a communication hole provided in a partition member between the combustion chamber and the filter chamber, thereby ensuring airtightness in these parts. Furthermore, by adopting such a method, it is possible to reduce manufacturing costs compared to using a sealed container.

JP 2018-69924 A JP 2008-296763 A

However, in the cylinder-type gas generator disclosed in Patent Document 2, the functions and characteristics of the holder described above require the ability to hold the igniter, receive the 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 a problem of high component costs for the holder.

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

Therefore, the present invention has been made to solve the above-mentioned problems, and aims to provide a gas generator that reduces manufacturing costs and weight.

The gas generator according to the present invention comprises a housing body, a holder assembly, and an igniter. The housing body is made of a cylindrical metal member that includes a combustion chamber in which a gas generating agent is housed. The holder assembly is inserted into the axial opening end of the housing body and includes a through-hole-like hollow opening extending along a direction parallel to the axial direction of the housing body. The igniter includes an ignition part that houses an ignition charge and a terminal pin connected to the ignition part, and at least a part of the igniter is disposed inside the hollow opening with the ignition part located on the combustion chamber side and the terminal pin located on the opposite side to the combustion chamber side. The holder assembly has a metal holder part that is located on the combustion chamber side and that receives and holds the igniter, and a resin connector part that is located on the opposite side to the combustion chamber side and that can receive a connector that is 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 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 that extends from the second body portion toward the combustion chamber side. The cylindrical portion is inserted into the open end of the housing body, and is inserted outside the first body portion at a portion that is located on the opposite side of the combustion chamber side as viewed from the annular protrusion. In the gas generator based on the present invention, the housing body at a portion corresponding to the cylindrical portion is reduced in diameter toward the radially inward direction, so that the cylindrical portion is sandwiched and compressed by the housing body at the reduced diameter portion and the first body portion, and thus the gap between the housing body and the first body portion is sealed by the cylindrical portion.

In the gas generator according to the present invention, the inner diameter of the cylindrical portion may be larger than the inner diameter of the second body portion, and an annular step surface connecting the inner peripheral surface of the second body portion and the inner peripheral surface of the cylindrical portion may be provided in the connector portion, so that a first chamber defined by the annular step surface and the inner peripheral surface of the cylindrical portion is provided at the axial end portion of the connector portion located on the combustion chamber side. In this case, it is preferable that the first body portion is inserted into the first chamber, and the axial end face of the first body portion located on the opposite side to the combustion chamber side abuts against the annular step surface.

In the gas generator according to the present invention, the inner diameter of the second body is larger than the inner diameter of the first body, so that a second chamber defined by the axial end face of the first body located on the opposite side to the combustion chamber side and the inner peripheral surface of the second body may be provided at the axial end of the holder assembly located on the opposite side to the combustion chamber side. In that case, it is preferable that the receiving portion of the connector to be connected to the terminal pin is constituted by the second chamber.

In the gas generator according to the present invention, the outer peripheral surface of the first body may be tapered toward the combustion chamber.

The gas generator according to the present invention may further include a filter disposed inside the housing body, and a partition member disposed inside the housing body to separate the space inside the housing body in the axial direction of the housing 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 body by welding.

The present invention makes it possible to produce a gas generator that is lightweight and has reduced manufacturing costs.

1 is a schematic diagram of a cylinder-shaped gas generator according to an embodiment. 2 is an enlarged cross-sectional view of the vicinity of an igniter of the cylinder-shaped gas generator shown in FIG. 1. 2 is an enlarged cross-sectional view of the vicinity of a partition member of the cylinder-shaped gas generator shown in FIG. 1. 4A to 4C are cross-sectional views showing a procedure for assembling a holder assembly in the cylinder-shaped gas generator shown in FIG. 1 . 4A to 4C are cross-sectional views showing a procedure for assembling a holder assembly in the cylinder-shaped gas generator shown in FIG. 1 . FIG. 13 is a cross-sectional view of a holder assembly of a cylinder-shaped gas generator according to first to fourth modified examples.

The following describes in detail an embodiment of the present invention with reference to the drawings. The embodiment described below illustrates the application of the present invention to a cylinder-type gas generator incorporated in a side airbag device. In the embodiments described below, the same or common parts are given the same reference numerals in the drawings, and their description will not be repeated.

Figure 1 is a schematic diagram of a cylinder-shaped gas generator according to an embodiment. Figures 2 and 3 are enlarged cross-sectional views of the vicinity of the igniter and the vicinity of the partition member of the cylinder-shaped gas generator shown in Figure 1, respectively. First, the configuration of the cylinder-shaped gas generator 1 according to this embodiment will be described with reference to Figures 1 to 3.

As shown in FIG. 1, the cylinder-type gas generator 1 according to this embodiment has a long, cylindrical outer shape and has a long, cylindrical housing with one end and the other end located in the axial direction closed. The housing includes a housing body 10, a holder assembly 20, and a closing member 30.

The housing, which is made up of the housing body 10, the holder assembly 20, and the blocking 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 primarily disposed, and a filter chamber S2 in which the filter 80 is disposed.

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 assembly 20 is made of a tubular member with a through-hole-like hollow opening extending along a direction parallel to the axial direction of the housing body 10, and has a holder part 20A and a connector part 20B, which will be described later. The blocking member 30 has a cup shape including a blocking part 31 and a side wall part 32, and has an annular recess 33 for crimping fixation, which will be described later, on the peripheral surface of the side wall part 32. This annular recess 33 for crimping fixation is formed so as to extend circumferentially on the peripheral surface of the side wall part 32.

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.

In particular, when the housing body 10 is made of a pressed rolled steel plate or an electric resistance welded pipe, it can be formed more cheaply and easily than when using metal components such as stainless steel or steel, and the weight can be significantly reduced.

On the other hand, the holder portion 20A and the blocking member 30 of the holder assembly 20 are made of metal members such as stainless steel, iron steel, aluminum alloy, stainless steel alloy, etc.

The holder assembly 20 is fixed to the housing body 10 so as to close one open end of the housing body 10 in the axial direction. 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 peripheral surface of the holder assembly 20, thereby crimping and fixing the holder assembly 20 to the housing body 10. As a result, one end of the housing in the axial direction is formed by the holder assembly 20. Details of the crimping and fixing will be explained later.

The blocking member 30 is fixed to the housing body 10 so as to block the other axial open end of the housing body 10. Specifically, with the blocking member 30 inserted into the other open end of the housing body 10, the portion of the housing body 10 corresponding to the annular recess 33 provided on the peripheral surface of the side wall portion 32 of the blocking member 30 is reduced in diameter radially inward and engages with the annular recess 33, thereby crimping and fixing the blocking member 30 to the housing body 10. As a result, the other axial end of the housing is formed by the blocking member 30.

These crimping methods are called eight-way crimping, which reduces the diameter of the housing body 10 radially inward in a generally uniform manner. 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 outer peripheral surface of the holder assembly 20 and the annular recess 33, respectively, preventing gaps from occurring between them.

The assembly structure of the blocking 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, instead of making the housing main body 10 and the blocking member 30 separate bodies, they may be constructed as a single member having a cylindrical shape with a bottom.

As shown in Figures 1 and 2, the igniter 40 is supported by the holder assembly 20 and is attached to the axial end of the housing. The igniter 40 is for burning the gas generating agent 60 and is installed so as to face the space inside the housing.

The igniter 40 is used to generate a flame and is also called a squib. The igniter 40 includes a base 41, an ignition portion 42, and a pair of terminal pins 43. The base 41 is a portion that holds the ignition portion 42 and the pair of terminal pins 43, and is also a portion that is fixed to the holder assembly 20. The pair of terminal pins 43 are inserted into the base 41 to hold them.

The 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 the ignition unit 42 to ignite the ignition charge.

More specifically, the 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 the squib cup, and an ignition charge is loaded into the squib cup so as to surround or be close to the resistor. In addition, an ignition charge may be loaded into the ignition unit 42 as necessary.

Here, the resistor generally uses a nichrome wire or a resistance wire made of an alloy containing platinum and tungsten, and the ignition charge generally uses ZPP (zirconium potassium perchlorate), ZWPP (zirconium tungsten potassium perchlorate), lead tricinate, etc. In addition, the transfer charge may use a composition made of a metal powder/oxidizer such as B/KNO ₃ , B/NaNO ₃ , Sr(NO ₃ ) ₂ , a composition made of titanium hydride/potassium perchlorate, or a composition made of B/5-aminotetrazole/potassium nitrate/molybdenum trioxide.

When a collision is detected, a predetermined amount of current flows through the resistor via the terminal pin 43. When a predetermined amount of current flows through the resistor, Joule heat is generated in the resistor, and the ignition charge begins to burn. The high-temperature heat particles generated by the combustion split open the squib cup that contains 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.

The igniter 40 is fixed to the holder assembly 20 with its ignition part 42 protruding toward the inside of the housing and a part of it disposed inside the hollow opening of the holder assembly 20. As a result, the ignition part 42 of the igniter 40 is located on the combustion chamber S1 side and its terminal pin 43 is located on the opposite side to the combustion chamber S1 side. Details of the fixing structure of the igniter 40 to the holder assembly 20 will be explained later.

As shown in Figures 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.

The partition member 50 has a cylindrical shape with a bottom, and is made of a metal member such as stainless steel, iron or 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.

The partition wall 51 has a score 51a on the main surface that contacts the filter 80. The score 51a is for the partition wall 51 to break and form an opening as the internal pressure of the combustion chamber S1 increases due to the combustion of the gas generating agent 60, and is composed of, for example, a number of grooves arranged radially and intersecting each other. The score 51a is provided in the part of the filter 80 that faces the hollow portion 81.

The partition member 50 is fixed by being inserted into the housing body 10 and joined to the housing body 10. More specifically, the partition member 50 is pressed into the inside of the housing body 10 and fixed by welding the annular wall portion 52 of the partition member 50 to the housing body 10 at or near the contact portion between them.

As a result, a welded portion 90 extending along the circumferential direction of the housing body 10 is formed on the housing 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 body 10.

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

The method of fixing the partition member 50 to the housing body 10 is not limited to the above-mentioned press-fitting and welding methods, and other fixing methods may be used. In this case, airtightness between the partition member 50 and the housing body 10 can be ensured by providing an O-ring, sealing tape, etc. at an appropriate position.

As shown in Figures 1 to 3, the gas generating agent 60 and the coil spring 70 are disposed in the space inside the housing, which is the space between the holder assembly 20 and the partition member 50 (i.e., the combustion chamber S1).

The gas generating agent 60 is an agent that generates gas by being ignited and burned by thermal particles generated by the activation of the igniter 40. It is preferable to use a non-azide gas generating agent as the gas generating agent 60, and the gas generating agent 60 is generally configured as a molded body containing a fuel, an oxidizer, and an additive.

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, etc. are preferably used.

As the oxidizing agent, for example, 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 are used. As the nitrate, for example, sodium nitrate, potassium nitrate, etc. are preferably used.

Additives include binders, slag formers, and combustion control agents. Suitable binders include organic binders such as metal salts of carboxymethylcellulose and stearates, and inorganic binders such as synthetic hydrotalcite and acid clay. Suitable slag formers include silicon nitride, silica, and acid clay. Suitable combustion control agents include metal oxides, ferrosilicon, activated carbon, and graphite.

The shape of the gas generating agent 60 may be granular, pellet-like, cylindrical, or disk-like. In addition, for cylindrical objects, perforated objects (such as single-hole or multi-hole cylindrical objects) with through holes inside the object may also be used. These shapes are preferably selected according to the specifications of the airbag device in which the cylindrical gas generator 1 is incorporated. For example, 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 60 is burned. In addition to the shape of the gas generating agent 60, it is also preferable to select the size and filling amount of the molded object taking into account the linear burning rate and pressure exponent of the gas generating agent 60.

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 positioned 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 approximately in parallel at a predetermined interval, and abuts against the gas generating agent 60.

As a result, the gas generating agent 60 is elastically biased toward the partition member 50 by the coil spring 70, preventing it from moving inside the housing.

Here, the end of the coil spring 70 on the holder assembly 20 side surrounds the ignition portion 42 of the igniter 40 so as to be in contact with the ignition portion 42 of the igniter 40 or to be positioned close to the ignition portion 42 of the igniter 40 with a predetermined clearance. By configuring it in this way, when the squib cup of the ignition portion 42 breaks open when the igniter 40 is activated, the degree to which the squib cup opens is regulated by the coil spring 70.

Therefore, by appropriately regulating the degree of opening of the squib cup, the direction of travel of the thermal particles generated in the ignition section 42 is narrowed to the axial direction of the housing 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 section 42 also has the function of giving directionality to the direction of travel of the thermal particles generated in the ignition section 42.

As shown in FIG. 1, a filter 80 is disposed in the space inside the housing, which is sandwiched between the blocking member 30 and the partition member 50 (i.e., the filter chamber S2). The filter 80 is a cylindrical member having a hollow portion 81 extending in a direction parallel to the axial direction of the housing body 10, with one axial end face abutting against the side wall portion 32 of the blocking member 30 and the other axial end face abutting against the bulkhead portion 51 of the partition member 50.

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

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

The filter 80 can also be a rolled up perforated metal plate. In this case, the perforated metal plate can be, for example, an expanded metal plate made by cutting staggered slits in a metal plate and expanding them to form holes and process them into a mesh-like shape, or a hook metal plate made by drilling holes in a metal plate and flattening the burrs that form around the holes by crushing them.

The housing body 10 in the portion defining the filter chamber S2 has multiple gas outlets 11 arranged along the circumferential and axial directions. These multiple gas outlets 11 are for directing the gas that has passed through the filter 80 to the outside of the housing.

Next, referring to FIG. 1, we will explain the operation of the cylinder-type gas generator 1 according to this embodiment during operation.

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

When the igniter 40 is activated, the pressure inside the ignition section 42 increases due to the combustion of the ignition charge or the transfer charge in addition to the ignition charge, which causes the squib cup of the ignition section 42 to split open, and the heat particles generated by the combustion of the ignition charge or the transfer charge in addition to the ignition charge flow out of the ignition section 42.

The thermal particles flowing out from the ignition section 42 are given directionality by the coil spring 70 described above, and thus 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.

As a result, the pressure in the combustion chamber S1 rises, and when the internal pressure of the combustion chamber S1 reaches a predetermined pressure, a fracture 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 in 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 through the opening.

As a result, the gas generated in the combustion chamber S1 flows into the filter chamber S2 through an opening formed in the partition member 50. The gas that flows into the filter chamber S2 flows axially through the hollow portion 81 of the filter 80, then turns radially and flows through the inside of the filter 80. During this process, the filter 80 removes heat and cools the gas, and the filter 80 removes slag contained in the gas.

After passing through the filter 80, the gas is ejected to the outside of the housing through a gas ejection port 11 provided in the housing body 10. The ejected gas is introduced into an airbag provided adjacent to the cylindrical gas generator 1, and inflates and deploys the airbag.

As described above, the cylinder-shaped gas generator 1 according to this embodiment has a holder assembly 20 as part of the housing, and the holder assembly 20 is attached to the opening end of the housing body 10 at the above-mentioned one end side. The configuration of the holder assembly 20, the fixing structure of the igniter 40 to the holder assembly 20, and the fixing structure of the holder assembly 20 to the housing body 10 will be described in detail below with reference to FIG. 2.

As shown in FIG. 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 to 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 above-mentioned one end side of the housing main body 10.

The holder portion 20A is composed of a flat, approximately disk-shaped member having a through-hole extending axially in the center, and includes a cylindrical first body portion 21 and an annular protrusion 22 that protrudes outward from the outer periphery of the first body portion 21.

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 above-mentioned 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 above-mentioned annular protrusion 22 is provided at the end of the first body portion 21 on the combustion chamber S1 side.

The holder portion 20A defines the combustion chamber S1 provided inside the housing body 10 and functions as a pressure bulkhead. Therefore, the holder portion 20A is made of a metal member as described above so that it has a high strength capable of withstanding the increase in internal pressure of the combustion chamber S1 when the cylinder-type gas generator 1 is activated.

The holder part 20A is also a member for receiving and holding the igniter 40, and has a concave-shaped accommodation part 23a at its axial end on the combustion chamber S1 side to receive the holder part 20A. This accommodation part 23a is connected to a through part provided in the holder part 20A. A crimping part 23b is provided at the end on the combustion chamber S1 side of the holder part 20A so as to surround the accommodation part 23a. The crimping part 23b is a part for crimping and fixing the igniter 40 to the holder part 20A.

The igniter 40 is fixed to the holder part 20A with its base 41 housed in the housing part 23a of the holder part 20A. Specifically, the base 41 is inserted into the housing part 23a of the holder part 20A and the base 41 is abutted against the bottom surface of the housing part 23a. In this state, the crimping part 23b provided on the holder part 20A is bent, and the igniter 40 is fixed to the holder part 20A. In this way, the igniter 40 is held by the holder part 20A.

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

The connector section 20B is composed of a generally cylindrical member having a through-hole extending in the axial direction in its center, and includes a cylindrical second body section 24, a cylindrical section 25 extending from one axial end of the second body section 24 along the axial direction, and a flange section 26 provided at the other axial end of the second body section 24.

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

Here, the holder part 20A is fixed by being pressed into the connector part 20B. More specifically, the first body part 21 of the holder part 20A is pressed into the cylindrical part 25 of the connector part 20B, and the first body part 21 and the cylindrical part 25 are in pressure contact with each other, so that the holder part 20A and the connector part 20B are fixed so that they do not easily come apart.

The connector portion 20B is for receiving a connector that is connected to the terminal pin 43 of the igniter 40. The terminal pin 43 of the igniter 40 is arranged inside this connector portion 20B. The through-hole provided in the connector portion 20B described above constitutes a portion for receiving this connector.

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

In addition, 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.

The connector portion 20B also functions as a member that ensures airtightness between the housing body 10 and the holder portion 20A. The part that ensures airtightness between the housing body 10 and the holder portion 20A is mainly the cylindrical portion 25 of the connector portion 20B.

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 radial inside to the radial outside 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.

The housing body 10 in the portion corresponding to the cylindrical portion 25 (i.e., the portion covering the cylindrical portion 25) is provided with a crimped portion 12 that narrows radially inward. By providing this crimped portion 12, the cylindrical portion 25 of the connector portion 20B made of a resin member is sandwiched between the crimped portion 12 of the housing body 10 made of a metal member and the first body portion 21 of the holder portion 20A made of a metal member, and the cylindrical portion 25 seals the gap between the housing body 10 and the first body portion 21.

When the crimping portion 12 is provided on the housing body 10, the tubular portion 25 is sandwiched between the housing body 10 and the first body portion 21, and compressive deformation occurs in the tubular portion 25 due to the load. As a result, the tubular portion 25 and the housing 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.

As a result, the cylindrical portion 25 is in close contact with the housing body 10 and the first body 21, and is interposed between the housing body 10 and the first body 21, thereby sealing the gap described above. Therefore, by configuring it in this way, it is possible to ensure airtightness in that area.

The material of the connector portion 20B is not particularly limited, but examples of suitable materials include 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.

In addition, the holder portion 20A is provided with an annular protrusion 22 at a position closer to the combustion chamber S1 than the first body portion 21. Therefore, the annular protrusion 22 also functions as a stopper that prevents the holder assembly 20 from falling out of the housing body 10. The stopper function of the annular protrusion 22 is exerted not only during the manufacture of the cylinder-type 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 the combustion chamber S1 during operation.

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

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

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

In addition, in the cylinder-shaped gas generator 1 according to this embodiment, the inner diameter R2 of the second body 24 is larger than the inner diameter R3 of the first body 21. As a result, a second chamber 28b is provided at the axial end of the holder assembly 20 opposite the combustion chamber S1, the second chamber 28b being defined by the axial end surface 21a of the first body 21, which is located opposite the combustion chamber S1, and the inner peripheral surface 24a of the second body 24.

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.

By configuring it in this way, the above-mentioned female connector to be provided in the connector portion 20B can be easily provided in the connector portion 20B, making it possible to further simplify the configuration of the holder assembly 20.

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

When assembling the holder assembly 20 to the housing body 10, first, as shown in FIG. 4, the holder part 20A is prepared with the igniter 40 attached thereto, and then this is assembled to the connector part 20B. Specifically, the first body part 21 of the holder part 20A is pressed into the cylindrical part 25 of the connector part 20B, and the holder part 20A with the igniter 40 attached thereto is assembled to the connector part 20B.

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 abutted against the flange portion 26 of the connector portion 20B.

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

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

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

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

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

Furthermore, by configuring the holder, which was previously constructed from a single metal part, as a holder assembly 20 that is 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 machining precision required when constructing 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.

Therefore, by using the cylinder-shaped gas generator 1 according to this embodiment, it is possible to reduce manufacturing costs and weight compared to conventional devices.

Figure 6 is a cross-sectional view of a holder assembly for a cylinder-shaped gas generator according to the first to fourth modified examples based on the embodiment described above. Below, the holder assembly 20 for the cylinder-shaped gas generators 1A to 1D according to the first to fourth modified examples will be described with reference to this Figure 6.

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

Specifically, in the holder assembly 20 according to the first modified example, the outer peripheral surface 21b of the first body 21 has an inclined shape that narrows toward the combustion chamber S1 side (i.e., the side opposite the connector portion 20B). Therefore, before the holder assembly 20 is assembled to the housing body 10, a gap is generated between the cylindrical portion 25 of the connector portion 20B and the first body 21 of the holder portion 20A.

When configured in this manner, when the crimping portion 12 is provided on the housing body 10, the tubular portion 25 of the connector portion 20B is compressed and deformed by receiving a load while tilting radially inward of the housing body 10. At this time, the load applied to the first body portion 21 of the holder portion 20A by the crimping portion 12 provided on the housing body 10 acts toward the side where the terminal pin 43 of the igniter 40 is located.

Therefore, when this configuration is adopted, the crimping portion 12 is more firmly attached to the holder portion 20A, and in addition to the effects described in the above embodiment, it is possible to obtain the effect of more reliably preventing the holder assembly 20 from falling off the housing main body 10.

The holder assemblies 20 of the cylinder-type gas generators 1B to 1D according to the second to fourth modified examples shown in Figures 6(B) to 6(D) differ from the above-described embodiment only in the shape of the cylindrical portion 25 of the connector portion 20B.

Specifically, in the holder assembly 20 according to the second to fourth modified examples, a concave portion is formed in advance on the outer peripheral surface of the cylindrical portion 25 at a position corresponding to the crimping portion 12 provided on the housing main body 10.

Here, in the holder assembly 20 according to the second modified example shown in FIG. 6(B), the concave portion is configured to have a C-shaped cross section, and in the holder assembly 20 according to the third modified example shown in FIG. 6(C), the thin-walled portion formed in the cylindrical portion 25 by providing the concave portion is configured to extend from a position corresponding to the crimped portion 12 provided on the housing 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 according to the fourth modified example shown in FIG. 6(D), the thin-walled portion formed in the cylindrical portion 25 by providing the concave portion is configured to extend from a position corresponding to the crimped portion 12 provided on the housing 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).

When configured in this manner, 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.

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.

The characteristic configurations shown in the above-mentioned embodiments of the present invention and their variations can of course be combined with each other within the scope of the spirit of the present invention.

In addition, in the above-mentioned embodiment and its modified examples of the present invention, 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 that have an elongated outer shape like a cylindrical gas generator.

As such, the above-described embodiments and their variations 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 those described in the claims.

1, 1A to 1D: Cylinder-type 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, 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 step surface, 28a: First chamber, 28b: Second chamber, 29: Seal 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: Bulkhead 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 welded portion, S1 combustion chamber, S2 filter chamber.

Claims (5)

A cylindrical metal housing body including a combustion chamber in which a gas generating agent is accommodated;
a holder assembly that is inserted into an axial opening end of the housing body and includes a through-hole-like hollow opening that extends along a direction parallel to the axial direction of the housing body;
an igniter including an ignition part containing an ignition charge and a terminal pin connected to the ignition part, the ignition part being positioned on the combustion chamber side and the terminal pin being positioned on the opposite side to the combustion chamber side, the igniter being at least partially disposed inside the hollow opening,
the holder assembly has 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 to 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 defining the hollow opening, and an annular protrusion protruding from the first body portion along a radial direction of the housing 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 outside the first body portion at a portion located on the opposite side to the combustion chamber side as viewed from the annular protrusion,
a gas generator in which a portion of the housing body corresponding to the cylindrical portion is narrowed radially inward, such that the cylindrical portion is sandwiched and compressed by the housing body at the narrowed portion and the first body portion, thereby sealing a gap between the housing body and the first body portion by the cylindrical portion. an inner diameter of the cylindrical portion is larger than an inner diameter of the second body portion, and an annular stepped surface connecting an inner peripheral surface of the second body portion and an inner peripheral surface of the cylindrical portion is provided on the connector portion, thereby providing a first chamber defined by the annular stepped surface and the inner peripheral surface of the cylindrical portion at an axial end portion of the connector portion located on the combustion chamber side;
2. The gas generator according to claim 1, wherein the first body portion is inserted into the first chamber, and an axial end face of the first body portion located opposite the combustion chamber side abuts against the annular step surface. Since the inner diameter of the second body portion is larger than the inner diameter of the first body portion, a second chamber is defined by an axial end surface of the first body portion located on the opposite side to the combustion chamber side and an inner circumferential surface of the second body portion, at an axial end portion of the holder assembly located on the opposite side to the combustion chamber side,
3. The gas generator according to claim 1, wherein the second chamber constitutes a receiving portion for a connector connected to the terminal pin. A gas generator according to any one of claims 1 to 3, in which the outer peripheral surface of the first body portion narrows toward the combustion chamber. a filter disposed inside the housing body;
a partition member that is disposed inside the housing body to partition an internal space of the housing body into a filter chamber in which the filter is disposed and the combustion chamber in an axial direction of the housing body,
5. The gas generator according to claim 1, wherein the partition member is fixed to the housing body by welding.

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