JP2023087958A - gas generator - Google Patents

Abstract

To provide a gas generator which permits weight-reduction and reduction of production cost while maintaining preferable gas output characteristics.SOLUTION: A gas generator 1A includes an igniter 40 assembled onto one end part of a housing, a gas generation agent 60 stored on an inner part of the housing and a coil spring 70 which is interposed between the above described one end part of the housing and the gas generation agent 60. The coil spring 70 separates the gas generation agent 60 from the igniter 40, at the same time, energizes the gas generating agent while turning this to the other end part side of the housing and, thereby, fixes the gas generation agent 60 onto the inner part of the housing. The coil spring 70 is arranged onto an axis approximately same with the ignition part 41 so as to surround the ignition part 41 without interposition of another member between the coil spring and the ignition part 41 so that an opening degree of a cup body 41c when the cup body 41c contained in the ignition part 41 of the igniter 40 is opened is regulated by the coil spring 70.SELECTED DRAWING: Figure 2

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas generator incorporated in an airbag device as an occupant protection device installed in an automobile or the like, and more particularly to a so-called cylinder-type gas generator having a long columnar outer shape suitable for incorporation in a side airbag device or the like. Concerning vessels.

2. Description of the Related Art Conventionally, from the viewpoint of protecting occupants of automobiles and the like, airbag devices, which are occupant protection devices, have been widely used. Airbag systems are installed to protect passengers from the impact that occurs in the event of a vehicle collision. By inflating and deploying the airbag instantaneously in the event of a vehicle collision, the airbag acts as a cushion for the passenger. It accepts the body.

The gas generator is incorporated in this airbag system, and when a vehicle or other vehicle collides, an igniter is ignited by electricity from the control unit, and the flame generated in the igniter burns the gas generating agent to instantaneously generate a large amount of gas. , the device that inflates and deploys the airbag.

Gas generators are available in various configurations based on specifications such as an installation position with respect to a vehicle or the like and output. One of them is called a cylinder type gas generator. Cylinder-type gas generators have an elongated cylindrical outer shape and are suitably incorporated in side airbag devices, curtain airbag devices, knee airbag devices, seat cushion airbag devices, and the like.

Generally, in a cylinder-type gas generator, an igniter is assembled to one end of a housing in the axial direction, a combustion chamber containing a gas generating agent is provided on the one end side, and the other end of the housing in the axial direction is provided. A filter chamber containing a filter is provided on the side of the housing, and a gas ejection port is provided on the peripheral wall portion of the housing that defines the filter chamber.

In the cylinder-type gas generator configured in this way, the gas generated in the combustion chamber flows into the filter chamber along the axial direction of the housing and passes through the inside of the filter. is ejected to the outside through the gas ejection port.

For example, Japanese Patent Laid-Open No. 2017-193191 (Patent Document 1) discloses a cylinder-type gas generator having such a configuration.

Here, in the cylinder-type gas generator disclosed in Patent Document 1, the gas generating agent is placed between the one end of the housing to which the igniter is assembled and the gas generating agent on the other end side of the housing. A coil spring is provided that biases toward. The coil spring is for fixing the gas generating agent inside the housing while maintaining an appropriate distance from the igniter attached to the one end of the housing to the gas generating agent.

Further, in the gas generator disclosed in Patent Document 1, a substantially cylindrical metal combustion control element is provided on the one end side of the housing so as to cover the ignition portion of the igniter, which is the portion in which the ignition charge is accommodated. A cover is provided. The combustion control cover is for efficiently guiding the hot particles generated by the igniter during operation to the gas generating agent. It gives you sex.

By using a cylinder type gas generator having such a configuration, it is possible to obtain good gas output characteristics during operation.

JP 2017-193191 A

However, in the case of the cylinder-type gas generator having the above configuration, it is necessary to provide a large number of parts in the one end portion of the housing. As a result, there arises a problem that the manufacturing cost increases. Further, if the number of parts can be reduced, the weight of the gas generator as a whole can be reduced accordingly.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a gas generator capable of reducing weight and manufacturing costs while maintaining good gas output characteristics. do.

A gas generator according to the present invention includes a housing, a gas generant, an igniter, and a coil spring. The housing is a long cylindrical member having a peripheral wall portion with one axial end portion and the other axial end portion closed. The gas generating agent is housed inside the housing. The igniter has an igniter containing an igniter for burning the gas generating agent. assembled in the department. The coil spring is interposed between the one end of the housing and the gas generating agent, and moves the gas generating agent away from the ignition portion while moving the gas generating agent toward the other end of the housing. to secure the gas generant within the housing. The igniter includes a cup body that splits when the igniter is ignited when the igniter is activated. In the gas generator according to the present invention, the coil spring is arranged between the ignition portion and the coil spring so that the degree of opening of the cup body when the cup body splits is restricted by the coil spring. It is arranged substantially coaxially with the ignition part so as to surround the ignition part without any other member interposed therebetween.

In the gas generator according to the present invention, the outer shape of the ignition portion may be substantially cylindrical, and the coil spring may be positioned on the one end side of the housing and have a constant inner diameter. and an enlarged diameter portion extending from the end of the cylindrical portion on the gas generating agent side toward the gas generating agent side and having an inner diameter that increases as it approaches the gas generating agent. You can stay. In that case, it is preferable that the portion of the coil spring surrounding the igniter is formed of the cylindrical portion.

In the gas generator according to the present invention, the inner diameter of the peripheral wall portion of the housing in which the gas generating agent is accommodated is R1, the outer diameter of the ignition portion is R2, and the point of the ignition portion is R2. The distance along the axial direction of the housing from the portion containing the explosive to the gas generating agent is defined as L1, and the portion containing the ignition charge of the ignition portion to the cylindrical portion and the enlarged diameter portion. L2 is the distance along the axial direction of the housing to the boundary between and C, and C is the clearance between the ignition portion and the cylindrical portion, 0<C≦(R1−R2)×(L2 /L1)/2 is preferably satisfied.

In the gas generator according to the present invention, the clearance is preferably 1.0 mm or less.

In the gas generator according to the present invention, a portion of the coil spring surrounding the ignition portion may be in contact with the ignition portion.

ADVANTAGE OF THE INVENTION According to this invention, the gas generator which becomes possible to reduce a weight and a manufacturing cost can be provided, maintaining a favorable gas output characteristic.

1 is a schematic diagram of a cylinder-type gas generator according to Embodiment 1. FIG. 2 is an enlarged cross-sectional view of the vicinity of an igniter of the cylinder-type gas generator shown in FIG. 1. FIG. 2 is an enlarged cross-sectional view of the vicinity of a partition member of the cylinder-type gas generator shown in FIG. 1. FIG. FIG. 5 is a diagram for explaining a preferred clearance range in the cylinder-type gas generator according to Embodiment 1; 8 is an enlarged cross-sectional view of the vicinity of an igniter of a cylinder-type gas generator according to Embodiment 2. FIG. FIG. 11 is an enlarged cross-sectional view of the vicinity of an igniter of a cylinder-type gas generator according to Embodiment 3; FIG. 11 is an enlarged cross-sectional view of the vicinity of an igniter of a cylinder-type gas generator according to Embodiment 4; 4 is a table showing test conditions and test results of a verification test;

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The embodiments shown below illustrate cases 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 denoted by the same reference numerals in the drawings, and the description thereof will not be repeated.

(Embodiment 1)
FIG. 1 is a schematic diagram of a cylinder-type gas generator according to Embodiment 1. FIG. 2 and 3 are an enlarged cross-sectional view near the igniter and an enlarged cross-sectional view near the partition member of the cylindrical gas generator shown in FIG. 1, respectively. First, the configuration of a cylinder-type gas generator 1A according to the present embodiment will be described with reference to FIGS. 1 to 3. FIG.

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

Inside the housing composed of the housing main body 10, the holder 20 and the closing member 30, an igniter 40, a partition member 50, a gas generating agent 60, a coil spring 70, a filter 80 and the like are accommodated as internal components. . Further, inside the housing, the combustion chamber S1 in which the gas generating agent 60 of the internal components described above is mainly arranged, and the filter chamber S2 in which the filter 80 is arranged are located.

The housing main body 10 constitutes a peripheral wall portion of the housing, and is composed of a long cylindrical member having openings formed at both ends in the axial direction. The holder 20 is a cylindrical member having a through portion 21 extending in the same direction as the axial direction of the housing body 10, and has an annular groove portion 22 for caulking and fixing, which will be described later, on its outer peripheral surface. The blocking member 30 is a disk-shaped member having a predetermined thickness, and has an annular groove 31 for caulking and fixing, which will be described later, on its peripheral surface. The annular grooves 22 and 31 for caulking are both formed on the outer peripheral surface of the holder 20 and the peripheral surface of the closing member 30 so as to extend along the circumferential direction.

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 a press formed by pressing a rolled steel plate typified by SPCE into a cylindrical shape. It may be configured by a molded product. Further, the housing body 10 may be composed of an electric resistance welded tube typified by STKM.

In particular, when the housing body 10 is composed of a press-formed product of rolled steel plate or an electric resistance welded pipe, the housing body 10 can be manufactured at a lower cost and more easily than when a member made of metal such as stainless steel or iron steel is used. can be formed, and a significant weight reduction is possible.

On the other hand, the holder 20 and the closing member 30 are made of metal members such as stainless steel, steel, aluminum alloy, and stainless alloy.

The holder 20 is fixed to the housing body 10 so as to close one axial open end of the housing body 10 . Specifically, in a state in which the holder 20 is inserted into the one open end of the housing body 10, a portion of the housing body 10 corresponding to the annular groove 22 provided on the outer peripheral surface of the holder 20 is radially inward. The holder 20 is caulked and fixed to the housing main body 10 by being contracted toward and engaged with the annular groove portion 22 . As a result, one axial end of the housing is formed by the holder 20 .

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, in a state in which the closing member 30 is inserted into the other open end of the housing body 10, the portion of the housing body 10 corresponding to the annular groove 31 provided on the peripheral surface of the closing member 30 is diametrically The closure member 30 is crimped and fixed to the housing body 10 by being contracted inward and engaged with the annular groove 31 . As a result, the other axial end of the housing is formed by the closing member 30 .

These crimping fixings are called eight-way crimping, in which the diameter of the housing main body 10 is substantially evenly reduced radially inward. By performing this eight-way crimping, the housing body 10 is provided with the crimped portions 12 and 13 . As a result, the crimped portions 12 and 13 come into direct contact with the annular groove portions 22 and 31, respectively, thereby preventing the formation of gaps therebetween.

The assembly structure of the holder 20 and the closing member 30 with respect to the housing body 10 is not limited to the assembly structure described above, and other assembly structures may be adopted. Alternatively, the housing main body 10 and the closing member 30 may be configured as one member having a cylindrical shape with a bottom instead of being separated.

As shown in FIGS. 1 and 2 , the igniter 40 is supported by the holder 20 and assembled to the above-described one 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 includes an ignition portion 41 and a pair of terminal pins 42 . The ignition portion 41 includes an ignition charge 41a, an embolus 41b, and a cup body 41c. Contained. A resistor (bridge wire) is attached to the interior of the ignition portion 41 so as to be connected to the pair of terminal pins 42, and the ignition portion 41 surrounds or contacts the resistor. An ignition charge 41a is filled inside. Further, a transfer charge may be loaded in the ignition part 41 as required.

Here, as the resistor, a nichrome wire, a resistance wire made of an alloy containing platinum and tungsten, or the like is generally used. Potassium chlorate), lead tricinate, and the like are used. In addition, as the transfer charge, a composition consisting of metal powder/oxidizing agent represented by B/KNO ₃ , B/NaNO ₃ , Sr(NO ₃ ) _2, etc., or a composition consisting of titanium hydride/potassium perchlorate and a composition comprising B/5-aminotetrazole/potassium nitrate/molybdenum trioxide. Note that the cup body 41c provided in the ignition portion 41 includes a metal cup.

A predetermined amount of current flows through the resistor via the terminal pin 42 when a collision is detected. When a predetermined amount of current flows through the resistor, Joule heat is generated in the resistor, and the ignition charge 41a starts burning. High-temperature thermal particles generated by the combustion cleave the cup body 41c containing the ignition charge 41a. The time from when the current flows through the resistor until the igniter 40 is activated is generally 2 milliseconds or less when the nichrome wire is used as the resistor.

The igniter 40 is fixed to the holder 20 by crimping portions 23 provided on the holder 20 . More specifically, the holder 20 has a crimped portion 23 for crimping and fixing the igniter 40 at its axial end facing the space inside the housing, and the igniter 40 is inserted into the through portion 21. The igniter 40 is clamped and fixed to the holder 20 by crimping the above-described crimping portion 23 while being inserted and abutted against the wall portion of the portion defining the through portion 21 of the holder 20 .

As a result, the igniter 40 is assembled to the holder 20 so that the igniter 41 protrudes toward the interior of the housing. Therefore, when the igniter 40 is actuated, the ignition charge 41a is ignited, causing the cup body 41c to split, and the cup body 41c opens along with the splitting.

Here, a sealing member 25 made of an O-ring or the like is interposed between the holder 20 and the igniter 40, so that the gap between the holder 20 and the igniter 40 is filled with the sealing member 25. The gap is thereby sealed. Therefore, by configuring in this way, it is possible to ensure the airtightness of the portion. In addition, the fixing method of the igniter 40 is not limited to the fixing method using the crimped portion 23 described above, and other fixing methods may be used.

A hollow portion 24 that is continuous with the through portion 21 described above is provided at the axial end portion of the holder 20 that is exposed to the outside. The recessed portion 24 forms a female connector portion for receiving a male connector (not shown) of a harness for connecting the igniter 40 and a control unit (not shown). , the portion near the tip of the terminal pin 42 of the igniter 40 is exposed. A male connector is inserted into the concave portion 24 as the female connector portion, thereby realizing electrical continuity between the core wire of the harness and the terminal pin 42 .

As shown in FIGS. 1 and 3, a partition member 50 is arranged at a predetermined position in the space inside the housing. The partition member 50 is a member for partitioning the space inside the housing into the combustion chamber S1 and the filter chamber S2 in the axial direction.

The partition member 50 has a substantially 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 plate-like partition wall portion 51 arranged perpendicular to the axial direction of the housing body 10 and a tubular plate-like annular wall portion 52 erected from the peripheral edge of the partition wall portion 51 . ing. The partition member 50 is arranged such that the outer main surface of the partition wall portion 51 is in contact with the filter 80 , and the outer peripheral surface of the annular wall portion 52 is in contact with the inner peripheral surface of the housing body 10 .

A score 51 a is provided on the main surface of the partition wall 51 that contacts the filter 80 . The score 51a is for forming an opening by breaking the partition wall 51 as the internal pressure of the combustion chamber S1 rises due to combustion of the gas generating agent 60. It consists of a plurality of grooves provided in the The score 51 a is provided in a portion of the filter 80 facing the hollow portion 81 .

An annular groove extending in the circumferential direction is provided in the peripheral portion of the partition wall portion 51 , which is the boundary with the annular wall portion 52 . An O-ring 53 is accommodated in this annular groove. With this configuration, the O-ring 53 is interposed between the partition member 50 and the housing body 10 and comes into pressure contact with both the partition member 50 and the housing body 10 .

Thereby, the gap between the partition member 50 and the housing body 10 is filled with the O-ring 53 . Therefore, by sealing the gap with the O-ring 53, the airtightness of the portion can be ensured.

The partition member 50 is fixed to the housing body 10 while being inserted into the housing body 10 . More specifically, the partition member 50 is press-fitted inside the housing body, whereby the annular wall portion 52 of the partition member 50 is in pressure contact with the housing body 10 . Therefore, the partition member 50 is fixed to the housing body 10 by the elastic restoring force of the annular wall portion 52 .

As shown in FIGS. 1 to 3, a gas generating agent 60 and a coil spring 70 are arranged in a space sandwiched between the holder 20 and the partition member 50 (that is, the combustion chamber S1) in the space inside the housing. It is

The gas generating agent 60 is a chemical that is ignited by thermal particles generated by the operation of the igniter 40 and burns to generate gas. As the gas generating agent 60, it is preferable to use a non-azide gas generating agent, and the gas generating agent 60 is generally configured as a compact containing a fuel, an oxidant, and an additive.

As the fuel, for example, a triazole derivative, a tetrazole derivative, a guanidine derivative, an azodicarbonamide derivative, a hydrazine derivative, or a combination thereof is used. Specifically, nitroguanidine, guanidine nitrate, cyanoguanidine, 5-aminotetrazole and the like are preferably used.

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, alkali metals, alkaline earth metals, transition metals, and ammonia. Nitrates and the like containing cations selected from are utilized. As nitrates, for example, sodium nitrate, potassium nitrate and the like are preferably used.

Additives include binders, slag forming agents, and combustion modifiers. As the binder, organic binders such as metal salts of carboxymethyl cellulose and stearates, and inorganic binders such as synthetic hydrotalcite and acid clay can be preferably used. As the slag forming agent, silicon nitride, silica, acid clay, etc. can be suitably used. Metal oxides, ferrosilicon, activated carbon, graphite and the like can be suitably used as combustion modifiers.

The shape of the molded body of the gas generating agent 60 includes various shapes such as granular shapes such as granules, pellets, and cylindrical shapes, and disk shapes. In addition, in the case of a columnar shape, a perforated shaped body having through holes inside the shaped body (for example, a single-hole cylindrical shape, a porous cylindrical shape, etc.) is also used. These shapes are preferably selected appropriately according to the specifications of the airbag device in which the cylindrical gas generator 1A is incorporated. It is preferable to select the optimum shape according to the specifications, such as selecting . In addition to the shape of the gas generating agent 60, it is preferable to appropriately select the size and filling amount of the compact in consideration of the linear burning velocity, pressure index, etc. of the gas generating agent 60.

As shown in FIGS. 1 and 2, a coil spring 70 is arranged in a space located closer to the holder 20 than the gas generating agent 60 in the combustion chamber S1. The coil spring 70 is formed by bending a metal wire, and includes a cylindrical portion 71 , an enlarged diameter portion 72 and a pressing portion 73 .

The cylindrical portion 71 is formed by spirally winding a metal wire so that the inner diameter of the cylindrical portion 71 is constant, so that the cylindrical portion 71 has a substantially cylindrical shape as a whole. The cylindrical portion 71 is located on the holder 20 side (that is, on the one end side of the housing), and one end in the axial direction is in contact with the holder 20 and/or the igniter 40 .

The enlarged diameter portion 72 is formed by spirally winding a metal wire so that the inner diameter increases toward the gas generating agent 60 side, thereby forming a hollow truncated conical shape as a whole. have. The enlarged diameter portion 72 extends from the other axial end of the cylindrical portion 71 (that is, the end on the gas generating agent 60 side) toward the gas generating agent 60 side. The outer diameter of the end portion of the enlarged diameter portion 72 on the side of the gas generating agent 60 is approximately equal to or slightly smaller than the inner diameter of the housing body 10 .

The pressing portion 73 is located at the end portion of the enlarged diameter portion 72 on the gas generating agent 60 side. By arranging them in a shape, they are configured to have a substantially disk-like shape as a whole. This pressing portion 73 is in contact with the gas generating agent 60 .

The coil spring 70 is arranged so as to surround the ignition portion 41 of the igniter 40 having a substantially cylindrical outer shape. That is, the coil spring 70 is arranged substantially coaxially with the ignition portion 41 so as to surround the ignition portion 41 without any other member interposed therebetween. As a result, the ignition portion 41 has its side surface surrounded by a portion of the cylindrical portion 71 of the coil spring 70 , and the space located between the ignition portion 41 and the gas generating agent 60 is the cylindrical portion of the coil spring 70 . Surrounded by the remaining portion of portion 71 and enlarged diameter portion 72 .

Here, the coil spring 70 is compressed by being sandwiched between the holder 20 and/or the igniter 40 and the gas generating agent 60 . Therefore, the gas generating agent 60 is elastically biased by the coil spring 70 toward the partition member 50 side (that is, the above-described other end portion side of the housing). It is prevented from moving. Therefore, by configuring in this manner, it is possible to prevent the gas generating agent 60 formed of a molded body from being pulverized by vibration or the like.

Also, when the coil spring 70 is assembled, the coil spring 70 is sandwiched and compressed by the holder 20 and/or the igniter 40 and the gas generating agent 60, so that the dimensions of various components housed inside the housing are reduced. Variation can also be absorbed by the coil spring 70 concerned.

Furthermore, by appropriately setting the axial length of the coil spring 70, it is possible to secure an appropriate distance from the igniter 40 assembled at one end of the housing to the gas generating agent 60. Therefore, when the igniter 40 is activated, the opening of the cup body 41c of the ignition portion 41 is not hindered by the gas generating agent 60, so that the gas generating agent 60 can be ignited early and reliably. .

In addition, in the cylindrical gas generator 1A according to the present embodiment, as described above, the coil spring 70 surrounds the ignition portion 41 and the space between the ignition portion 41 and the gas generating agent 60. Accordingly, when the cup body 41c of the ignition portion 41 is cleaved when the igniter 40 is actuated, the degree of opening of the cup body 41c is regulated by the coil spring 70. As shown in FIG. As a result, it is possible to impart directivity to the thermal particles generated by the ignition section 41, the details of which will be described later.

As shown in FIG. 1, a filter 80 is arranged in a space sandwiched between the closing member 30 and the partition member 50 (that is, the filter chamber S2) in the space inside the housing. The filter 80 is a cylindrical member having a hollow portion 81 extending in the same direction as the axial direction of the housing body 10. One axial end surface of the filter 80 is in contact with the closing member 30, and the other axial end surface is in contact with the closing member 30. The end face is in contact with the partition member 50 .

The filter 80 functions as a cooling means for cooling the gas by removing high-temperature heat from the gas when the gas generated by the combustion of the gas generating agent 60 passes through the filter 80. It also functions as a removing means for removing slag (residue) and the like contained in. By using the filter 80 made of a cylindrical member as described above, the flow resistance to the gas flowing in the filter chamber S2 during operation can be kept low, and efficient gas flow can be realized. .

As the filter 80, it is preferable to use one composed of an aggregate of metal wires or metal nets made of stainless steel, steel, or the like. Specifically, a knitted wire mesh, a plain-woven wire mesh, an aggregate of crimp-woven metal wire rods, or a product obtained by pressing these together can be used.

As the filter 80, a wound perforated metal plate or the like can also be used. In this case, the perforated metal plate may be, for example, an expanded metal obtained by cutting a metal plate in a zigzag pattern and expanding the cuts to form holes to form a mesh, or a metal plate with holes and A hook metal or the like can be used by flattening the burrs formed on the periphery of the hole by crushing them.

A portion of the housing body 10 defining the filter chamber S2 is provided with a plurality of gas ejection ports 11 along the circumferential direction and the axial direction. These multiple gas ejection ports 11 are for leading out the gas after passing through the filter 80 to the outside of the housing.

Next, referring to FIG. 1, the operation of the cylinder-type gas generator 1A according to the present embodiment will be described.

Referring to FIG. 1, when a vehicle equipped with a cylinder-type gas generator 1A according to the present embodiment collides, the collision is detected by collision detection means separately provided in the vehicle. The igniter 40 is activated by energization from a control unit separately provided in the vehicle.

When the igniter 40 is activated, the igniter 41a or the transfer charge in addition to the igniter 41a burns, thereby increasing the pressure in the igniter 41, which causes the cup body 41c of the igniter 41 to open and the igniter 41a to burn. Thermal particles generated thereby flow out of the ignition portion 41 .

Directivity is imparted to the thermal particles flowing out from the ignition part 41 by the coil spring 70 described above, so that they reach the gas generating agent 60 . The hot particles reaching the gas generating agent 60 burn the gas generating agent 60, thereby generating a large amount of gas in the combustion chamber S1.

When a large amount of gas is generated in the combustion chamber S1, the pressure and temperature of the combustion chamber S1 rise, and the internal pressure of the combustion chamber S1 reaches a predetermined pressure, and the score 51a of the partition member 50 is provided. Part breaks. As a result, a communication hole is formed in the partition member 50 at a portion facing the hollow portion 81 of the filter 80, and the combustion chamber S1 and the filter chamber S2 are communicated with each other through the communication hole.

Accordingly, the gas generated in the combustion chamber S1 flows into the filter chamber S2 through the communicating holes formed in the partition member 50. As shown in FIG. The gas that has flowed into the filter chamber S2 flows in the hollow portion 81 of the filter 80 along the axial direction and then changes direction in the radial direction to flow through the inside of the filter 80 . At that time, heat is removed by the filter 80 to cool the gas, and slag contained in the gas is removed by the filter 80 .

After passing through the filter 80 , the gas is ejected to the outside of the housing through the gas ejection port 11 . The gas ejected from the gas ejection port 11 is introduced into an airbag provided adjacent to the cylinder-type gas generator 1A to inflate and deploy the airbag.

Here, as described above, in the cylindrical gas generator 1A according to the present embodiment, as shown in FIG. The coil spring 70 interposed between is arranged substantially coaxially with the ignition portion 41 of the igniter 40 so as to surround the ignition portion 41 without any other member interposed therebetween. there is Moreover, the coil spring 70 surrounds not only the ignition portion 41 of the igniter 40 but also the space between the ignition portion 41 and the gas generating agent 60 .

With this configuration, firstly, since the ignition portion 41 is surrounded by the cylindrical portion 71 of the coil spring 70, when the cup body 41c of the ignition portion 41 splits, the cup body 41c Therefore, it is possible to prevent the side wall portion from being cleaved and the side wall portion from deforming outward. Therefore, the opening can be formed mainly at the tip portion of the cup body 41c which is located on the gas generating agent 60 side.

Secondly, when the cup body 41c of the ignition portion 41 is cleaved to form an opening at the tip of the cup body 41c, the open portion of the cup body 41c is mainly the expanded diameter portion 72 of the coil spring 70. As a result, further outward deformation of the open portion of the cup body 41c can be suppressed. Therefore, the expanded diameter portion 72 of the coil spring 70 and the open portion of the cup body 41c also function as a kind of guide that determines the traveling direction of the thermal particles.

Therefore, the traveling direction of the thermal particles generated by the ignition portion 41 is narrowed in the axial direction of the housing body 10 , and the thermal particles can be efficiently guided to the gas generating agent 60 . Therefore, the coil spring 70 not only functions to fix the gas generating agent 60 inside the housing, but also efficiently guides the heat particles generated by the igniter 40 to the gas generating agent 60 during operation. This will also exhibit the function of preventing combustion, eliminating the need to install a member such as a combustion control cover that was required in the past.

As described above, by using the cylinder-type gas generator 1A according to the present embodiment, it becomes possible to reduce the number of parts as compared with the conventional one, which not only simplifies the assembly work but also , the weight of the gas generator as a whole can be reduced. Therefore, it is possible to achieve both weight reduction and manufacturing cost reduction while maintaining good gas output characteristics.

In order to efficiently guide the thermal particles generated by the ignition part 41 to the gas generating agent 60, it is necessary to give the thermal particles an appropriate directivity. The degree of flexibility is determined, in particular, by the clearance between the ignition portion 41 and the cylindrical portion 71 of the coil spring 70 that surrounds the ignition portion 41 . A preferred range of this clearance will be described below with reference to FIG. FIG. 4 is a diagram for explaining a preferable clearance range in the cylinder-type gas generator according to the present embodiment.

It is preferable that there is no clearance between the ignition portion 41 and the cylindrical portion 71 from the viewpoint of preventing cracking or deformation of the side wall portion of the cup body 41c. However, it is not always easy to press-fit the coil spring 70 made of a metal wire into the ignition portion 41, and from the viewpoint of facilitating the assembly work, it is desirable to provide a slight clearance.

It has been confirmed that this clearance is preferably at least 1.0 mm or less from the results of a verification test described later, but the upper limit is that the enlarged diameter portion 72 and the open portion of the cup body 41c serve as a kind of guide. can be determined as follows.

That is, referring to FIG. 4, the inner diameter of the housing body 10 defining the space in which the gas generating agent 60 is accommodated is R1, the outer diameter of the ignition portion 41 is R2, and the ignition agent 41a of the ignition portion 41 is Let L1 be the distance along the axial direction of the housing body 10 from the portion where the gas generating agent 60 is accommodated, and the cylindrical portion 71 and the enlarged diameter portion 72 extend from the portion of the ignition portion 41 where the ignition charge 41a is accommodated. When the distance along the axial direction of the housing body 10 to the boundary of is L2, the clearance C between the ignition portion 41 and the cylindrical portion 71 is 0<C≦(R1−R2)×(L2/ It is preferable that the condition of L1)/2 (hereinafter referred to as "first condition") is satisfied.

By satisfying the first condition, the gas generating agent 60 is positioned within a range where the hot particles are guided by the enlarged diameter portion 72 and the open portion of the cup body 41c when viewed from the ignition portion 41. Therefore, the hot particles can be guided to the gas generating agent 60 very efficiently. Therefore, in order to reliably obtain the above effects, it is preferable that the first condition is satisfied.

Further, referring to FIG. 4, when the outer diameter of the ignition portion 41 is R2, and the inherent elongation rate of the material of the cup body 41c constituting the ignition portion 41 of the igniter 40 is e, the ignition portion 41 and the cylindrical portion 71 preferably satisfies the condition 0≦C≦e×R/2 (hereinafter referred to as the “second condition”). Here, the elongation rate e is the ratio of the elongation generated between the marked lines on the test piece and the distance between the marked lines until the test piece breaks in a tensile test using the material, expressed as a percentage. To tell.

By satisfying the second condition, when the igniter 40 is activated, the deformation of the cup body 41c constituting the ignition part 41 contacts the cylindrical part 71 before the cup body 41c breaks. , thereby suppressing further deformation of the cup body 41c. Therefore, in order to reliably obtain the above-described effects, it is preferable that the second condition is satisfied.

(Embodiment 2)
FIG. 5 is an enlarged cross-sectional view of the vicinity of the igniter of the cylinder-type gas generator according to Embodiment 2. FIG. Next, referring to FIG. 5, a cylinder-type gas generator 1B according to this embodiment will be described.

As shown in FIG. 5, in the cylindrical gas generator 1B according to the present embodiment, the inner diameter of the cylindrical portion 71 of the coil spring 70 is smaller than that of the cylindrical gas generator 1A according to the first embodiment. are different, so that the cylindrical portion 71 is in contact with the ignition portion 41 . That is, there is no clearance between the ignition portion 41 and the cylindrical portion 71 in the cylindrical gas generator 1B according to the present embodiment.

Even in the case of such a configuration, an effect similar to the effect described in the above-described first embodiment can be obtained, and it is possible to achieve both weight reduction and manufacturing cost reduction while maintaining good gas output characteristics. can be realized. Furthermore, in the case of such a configuration, it is necessary to press-fit the coil spring 70 into the ignition portion 41 during the assembly work, and although the workability is slightly inferior to the case where a clearance is provided, it is more efficient. It is possible to obtain the effect of reliably preventing the side wall portion of the cup body 41c from being cleaved or deformed.

(Embodiment 3)
6 is an enlarged cross-sectional view of the vicinity of the igniter of the cylinder-type gas generator according to Embodiment 3. FIG. Next, referring to FIG. 6, a cylinder-type gas generator 1C according to the present embodiment will be described.

As shown in FIG. 6, in the cylindrical gas generator 1C according to the present embodiment, when compared with the cylindrical gas generator 1B according to the second embodiment described above, the metal of the cylindrical portion 71 of the coil spring 70 is reduced. Only the number of turns of wire is different. Specifically, in the cylinder-type gas generator 1C, the portion of the cylindrical portion 71 of the coil spring 70 that surrounds the ignition portion 41 of the igniter 40 has a narrow pitch of the metal wire, so that the portion The number of turns of the cylindrical portion 71 is increased.

Even when configured in this way, the effect according to the effect described in the above-described second embodiment can be obtained, and it is possible to achieve both weight reduction and manufacturing cost reduction while maintaining good gas output characteristics. can be realized. Furthermore, in the case of such a configuration, the deformation of the side wall portion of the cup body 41c during operation of the igniter 40 is more reliable by the increase in the number of turns of the metal wire in the cylindrical portion 71 of the coil spring 70. It is possible to obtain the effect of being able to suppress the

(Embodiment 4)
FIG. 7 is an enlarged sectional view of the vicinity of an igniter of a cylinder-type gas generator according to Embodiment 4. FIG. Next, a cylinder-type gas generator 1D according to this embodiment will be described with reference to FIG.

As shown in FIG. 7, a cylindrical gas generator 1D according to the present embodiment has a cylindrical portion 71 of a coil spring 70 and an expanded portion when compared with the cylindrical gas generator 1C according to the third embodiment described above. Only the configuration of the diameter portion 72 is different. Specifically, in the cylindrical gas generator 1D, the axial length of the cylindrical portion 71 of the coil spring 70 is longer than that of the cylindrical gas generator 1C described above, and the coil spring 70 The axial length of the enlarged diameter portion 72 of is configured to be shorter.

That is, in the cylinder-type gas generator 1D according to the present embodiment, only the end portion of the portion adjacent to the pressing portion 73 of the coil spring 70 is configured as the enlarged diameter portion 72, so that the ignition portion of the igniter 40 41 , most of the space between the ignition part 41 and the gas generating agent 60 is surrounded by the cylindrical part 71 of the coil spring 70 .

Even in the case of such a configuration, the same effect as in the case of the above-described third embodiment can be obtained, and it is possible to achieve both weight reduction and manufacturing cost reduction while maintaining good gas output characteristics. It will be possible.

(verification test)
Verification tests conducted to confirm the effects of the present invention will be described below. In the verification test, cylinder-type gas generators according to Verification Examples 1 to 3 based on the above-described Embodiment 1 were actually manufactured as prototypes. Experimental cylinder-type gas generators were produced, and the gas output characteristics were measured by actually operating the cylinder-type gas generators according to Verification Examples 1 to 3 and Comparative Example. FIG. 8 is a table showing test conditions and test results of the verification test.

As shown in FIG. 8, the cylinder-type gas generators according to Verification Examples 1 to 3 are provided with the coil spring 70 described above. (See FIG. 2, etc.). Here, in Verification Examples 1 to 3, the inner diameters of the coil springs 70 used are different, but the wire diameter, the number of turns, etc. are the same.

On the other hand, the cylinder-type gas generator according to the comparative example does not include the coil spring 70 described above, and instead of this, only the pressing portion 73 of the coil spring 70 is fixed to the housing body 10, thereby enabling ignition. The distance between the ignition part 41 of the device 40 and the gas generating agent 60 is set to be the same as that of the cylindrical gas generators according to Verification Examples 1 to 3 described above.

Here, in the cylinder-type gas generators according to Verification Examples 1 to 3 and the Comparative Example, they are configured so that they are different from each other only in the presence or absence of the coil spring and the inner diameter of the coil spring, and all other configurations are the same. It is configured to be

That is, the inner diameter R1 of the housing body 10 is 17.4 mm in both cases, and the outer diameter R2 of the ignition portion 41 is 8.05 mm in both cases. In addition, the distance L1 along the axial direction of the housing body 10 from the portion of the ignition portion 41 containing the ignition charge 41a to the gas generating agent 60 is 10.5 mm in any of these cases. A distance L2 along the axial direction of the housing body 10 from the portion in which the ignition charge 41a is accommodated to the boundary between the cylindrical portion 71 and the enlarged diameter portion 72 is 2.3 mm.

The clearance in the cylinder-type gas generators according to Verification Examples 1 to 3 is the above-described clearance C (that is, the distance between the ignition portion 41 and the cylindrical portion 71), and the cylinder-type gas generation according to the comparative example. The clearance in the vessel is the distance between the ignition part 41 and the housing body 10. As shown in FIG.

In the verification test, two samples each of the cylindrical gas generators according to Verification Examples 1 to 3 and Comparative Example were prepared, each of which was placed in a sealed tank and operated. The change in internal pressure over time was measured. The output index in FIG. 8 is used when evaluating the gas output characteristics, and indicates the time from the actuation of the igniter until the pressure in the tank changes.

As shown in FIG. 8, based on the results of the verification test, in the cylinder-type gas generators according to Verification Examples 1 to 3 in which the clearance C between the ignition portion and the cylindrical portion is 1.0 mm or less, It was confirmed that the above output index was improved as compared with the cylindrical gas generator according to the comparative example in which no coil spring was provided. That is, it has been experimentally confirmed that the gas output can be obtained earlier from the operation by regulating the degree of opening of the cup body 41c of the ignition part 41 by the coil spring 70, and furthermore, It was confirmed that the output index improved more as the clearance C decreased.

(Other forms, etc.)
In the first to fourth embodiments of the present invention described above, a coil spring configured to include a cylindrical portion and an enlarged diameter portion is used as the coil spring that imparts directivity to the thermal particles generated in the ignition portion of the igniter. However, it is not always necessary to use a coil spring with such an outer shape. Coil springs of various shapes can be used, such as coil springs or coil springs configured to have the same inner diameter except for the pressing portion. In either case, if the coil spring is configured to restrict the degree of opening of the cup body of the ignition portion, a corresponding effect can be obtained. Also, the wire diameter, the number of turns, the material, etc. of the coil spring can naturally be changed as appropriate.

In addition, in the first to fourth embodiments of the present invention described above, the cylinder-type gas generator having no auto-ignition agent, which automatically ignites without depending on the operation of the igniter, has been exemplified and explained. The cylinder-type gas generator may be configured so as to be provided. The auto ignition agent spontaneously ignites at a temperature lower than that of the gas generating agent. This is to prevent abnormal operation from being induced by external heating of the mold gas generator. When the auto-ignition agent is provided in the cylinder-type gas generator, for example, the auto-ignition agent may be arranged in the space inside the combustion chamber and in contact with the partition member.

In addition, in the first to fourth embodiments of the present invention described above, the case where the present invention is applied to the cylinder-type gas generator incorporated in the side airbag device has been described as an example. is not limited to this, and has a long outer shape similar to a cylinder type gas generator incorporated in a curtain airbag device, a knee airbag device, a seat cushion airbag device, etc. It can also be applied to a so-called T-shaped gas generator.

Thus, the above-described embodiments disclosed this time are illustrative in all respects and are not restrictive. The technical scope of the present invention is defined by the scope of claims, and includes all changes within the meaning and scope of equivalents to the description of the scope of claims.

1A to 1D cylinder type gas generator, 10 housing body, 11 gas ejection port, 12, 13 crimped portion, 20 holder, 21 through portion, 22 annular groove portion, 23 crimped portion, 24 recess, 25 sealing member, 30 closing member , 31 annular groove portion, 40 igniter, 41 ignition portion, 41a ignition powder, 41b embolism, 41c cup body, 42 terminal pin, 50 partition member, 51 partition portion, 51a score, 52 annular wall portion, 53 O-ring, 60 gas Generating agent 70 Coil spring 71 Cylindrical part 72 Expanded diameter part 73 Pressing part 80 Filter 81 Hollow part S1 Combustion chamber S2 Filter chamber.

Claims (5)

a long tubular housing having a peripheral wall portion with one axial end and the other axial end closed;
a gas generant contained within the housing;
An igniter having an igniter containing an ignition charge for burning the gas generating agent, and assembled to the one end of the housing so that the igniter protrudes toward the inside of the housing. vessel and
It is interposed between the one end of the housing and the gas generating agent, and biases the gas generating agent toward the other end of the housing while separating the gas generating agent from the ignition portion. and a coil spring that fixes the gas generating agent inside the housing,
The ignition part includes a cup body that is cleaved when the ignition charge is ignited when the igniter is actuated,
The coil spring moves the ignition portion without any other member interposed between the coil spring and the ignition portion so that the degree of opening of the cup body when the cup body splits is restricted by the coil spring. A gas generator arranged substantially coaxially with the ignition part so as to surround it. The igniter has a substantially cylindrical outer shape,
The coil spring includes a cylindrical portion positioned on the one end side of the housing and having a constant inner diameter, and extending from the end of the cylindrical portion on the side of the gas generating agent toward the gas generating agent. and an enlarged diameter portion whose inner diameter increases as it approaches the gas generating agent,
2. The gas generator according to claim 1, wherein said coil spring surrounding said igniter is constituted by said cylindrical portion. The inner diameter of the peripheral wall portion of the housing in the portion containing the gas generating agent is R1, the outer diameter of the ignition portion is R2, and the gas is generated from the portion of the ignition portion containing the ignition agent. L1 is the distance along the axial direction of the housing to the igniter, and the axial direction of the housing is from the portion of the igniter portion containing the igniter to the boundary between the cylindrical portion and the enlarged diameter portion. where L2 is the distance along and C is the clearance between the ignition portion and the cylindrical portion, the condition 0<C≦(R1−R2)×(L2/L1)/2 is satisfied. 3. The gas generator of claim 2, wherein 4. The gas generator according to claim 3, wherein said clearance is 1.0 mm or less. 3. The gas generator according to claim 1, wherein a portion of said coil spring surrounding said ignition portion is in contact with said ignition portion.

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