JP2017007456A - Gas generator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gas generator in which not only a cylindrical gas generating agent inside a working gas generation chamber can be easily secured but also combustion performance of the gas generating agent as can be achieved as designed.SOLUTION: A gas generator 100 includes: a long substantially cylindrical housing 10; a holder 20 fitted to one opening end of the housing 10; and a closing member 12 fitted to the other end part of the housing 10 so as to close the other opening end of the housing 10. An igniter 50 as ignition means of a gas generating agent is disposed at one axial-direction end part of the housing 10. A coil spring 60 comprises a large diameter part which is densely wound spirally along an inner wall of the housing 10, and a diameter-reduced portion which is sparsely wound at a predetermined interval. The coil spring is provided so as to apply an elastic force to the gas generating agent 30 while one end part is in contact with the holder 20 and the other end part is in contact with at least a part of a periphery of a through-hole on one end side of the gas generating agent 30.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a gas generator incorporated in an airbag device as an occupant protection device mounted on an automobile or the like, and more particularly to a so-called cylinder type gas generator having a long cylindrical outer shape.

  In cylinder-type gas generators, while miniaturization is progressing, in order to make it easier to load a gas generating agent in the miniaturized gas generator, combustion performance is expanded by expanding the ignition area by making it cylindrical. In recent years, a plurality of cylindrical gas generating agents having an outer diameter close to the inner diameter of the housing are used side by side in the axial direction (for example, see Patent Document 1 below), or A molded tubular gas generating agent may be used.

US Pat. No. 7,967,333

  However, in the gas generator disclosed in Patent Document 1, the axial lengths of the cylindrical gas generating agents arranged in a line in the axial direction in the working gas generation chamber in the housing and the axial direction of the working gas generation chamber in the housing. If the length of the gas generating agent is not precisely matched, the position of the gas generating agent cannot be stabilized and fixed by the distributor, and the position of the gas generating agent may be displaced by vibration. When such misalignment of the gas generating agent in the working gas generation chamber occurs, the flame from the igniter flowing into the working gas generation chamber through the holes provided in the distributor is as designed. The gas generating agent may not hit the surface of the gas generating agent, and the combustion performance of the gas generating agent may not be achieved as designed. This point is considered to be applicable to the case of using an integrally molded cylindrical gas generating agent.

  Accordingly, an object of the present invention is to provide a gas generator that can not only easily fix a cylindrical gas generating agent in a working gas generating chamber but also achieve the combustion performance of the gas generating agent as designed. It is what.

(1) In the gas generator of the present invention, a cylindrical gas generating agent having a through hole along the axial direction in the substantially central portion and at least one groove along the axial direction on the outer periphery is burned. A long cylindrical housing containing therein a working gas generation chamber in which a working gas is generated and a filter chamber containing a filter through which the working gas generated in the working gas generation chamber passes. A gas generating agent igniting means disposed in one end of the housing in the axial direction and capable of igniting and burning the gas generating agent in the working gas generating chamber; The one end portion is in contact with or attached to the gas generating agent ignition means, and at least a part of the other end portion is in contact with at least a portion around the through hole on one end side of the gas generating agent. Elastic on the other end of the And at least a part of the winding spring is gradually reduced in diameter from the gas generating agent ignition means to the gas generating agent. The winding portion of the diameter portion has a predetermined interval, and the filter chamber is located on the other end side in the axial direction of the housing with respect to the working gas generation chamber, and the peripheral wall of the portion defining the filter chamber of the housing The part is provided with a plurality of gas outlets for ejecting the working gas that has passed through the filter to the outside, and the gap between the gas generating agent ignition means and one end of the housing is closed. At least a part of the gas generating agent ignition means is covered with one end of the housing, and the gas generating agent ignition means is fixed to the housing. Here, the cylindrical gas generating agent having a through-hole has an outer diameter close to the size of the inner diameter of the housing, and a plurality of short cylindrical gas generating agents arranged in the axial direction and integrally molded. Including a long cylindrical shape.

  According to the configuration of (1) above, the cylindrical gas generating agent in the working gas generation chamber can be easily fixed in the housing. Further, at least a part of the winding spring is gradually reduced in diameter from the gas generating agent igniting means to the gas generating agent, and the winding interval of the reduced diameter portion is a predetermined interval. The flow path of the flame generated from the direct flow toward the gas generating agent 30, the one that is changed by colliding with the winding spring, and that flows easily to the through hole of the gas generating agent, flows to the inner wall side of the housing, The gas generating agent is diverted into one that easily flows into the groove. As a result, the flame diffuses and easily comes into contact with the surface of the gas generating agent, and the ignition efficiency of the gas generating agent is improved. For example, the gas generator can be made smaller or longer than before. Even if the size is reduced, the combustion performance of the gas generating agent (for example, generating a predetermined amount of gas in a certain time) can be achieved as designed.

(2) In the gas generator of the above (1), it is preferable that the winding spring includes a large diameter portion having a diameter larger than that of the reduced diameter portion in addition to the reduced diameter portion.

  According to the configuration of (2) above, since the winding spring has a large-diameter portion, the winding spring is stably fixed particularly when the outer diameter of the large-diameter portion is close to the inner diameter of the housing. be able to.

(3) In the gas generator of the above (2), it is preferable that the winding interval (pitch) of the large diameter portion is smaller than the winding interval of the reduced diameter portion.

  According to the configuration of the above (3), since the interval between the large diameter portions of the winding spring is smaller than the interval between the reduced diameter portions, when the winding spring contracts, the large diameter portion is less than the reduced diameter portion. Will be deformed first, and the reduced diameter portion will hardly be deformed. Therefore, even if the reduced diameter portion is mounted in the housing, it keeps a predetermined interval, so that the flame flow path of the ignition means does not change and stable ignition is realized.

(4) In the gas generator of the above (2) or (3), it is preferable that one end portion of the winding spring is wound around at least the tip portion of the gas generating agent ignition means.

  According to the configuration of (4) above, the position of the winding spring can be further stabilized in the housing, so that the flow path of the flame generated from the gas generating agent ignition means can be made as designed. Therefore, the combustion performance of the gas generating agent can be achieved as designed.

(5) In the gas generators of the above (1) to (4), it is preferable that the outer diameter of the gas generating agent is substantially the same as the inner diameter of the housing.

  According to the configuration of (5) above, the gas generating agent is not displaced in the direction substantially perpendicular to the axis in the housing, so the flow path of the flame generated from the gas generating agent ignition means is as designed. be able to. Therefore, the combustion performance of the gas generating agent can be achieved as designed.

(A) is a schematic diagram which shows the internal structure of the gas generator which concerns on embodiment of this invention which represented a part with a cross section, (b) is the elements on larger scale of (a). (A) is a perspective view of the winding spring in the gas generator of FIG. 1, (b) is a top view of (a), (c) is a figure which shows the modification of (a). It is a figure which shows the gas generating agent of the gas generator of FIG.

<First Embodiment>
Hereinafter, with reference to FIGS. 1-3, the internal structure of the cylinder type gas generator which concerns on embodiment of this invention is demonstrated.

(Configuration of gas generator 100)
The gas generator 100 has a long and substantially cylindrical outer shape, and closes the housing 10, the holder 20 attached to one open end of the housing 10, and the other open end of the housing 10. And a closing member 12 attached to the other end of the housing 10.

  The housing 10 is formed of a long cylindrical member having openings at both ends in the axial direction. The closing member 12 is made of a disk-shaped member having a predetermined thickness, and has an annular groove portion 13 for fixing by caulking, which will be described later, on the peripheral surface thereof. The annular groove 13 for caulking and fixing is formed on the peripheral surface of the closing member 12 so as to extend in the circumferential direction. A gas outlet 11 is provided on the peripheral wall near the end of the housing 10 where the closing member 12 is attached. The gas ejection ports 11 are holes for ejecting the gas generated inside the gas generator 100 to the outside, and a plurality of gas ejection ports 11 are provided along the circumferential direction and the axial direction of the housing 10.

  The closing member 12 is made of a metal such as stainless steel, steel, an aluminum alloy, or a stainless alloy, and is made of a disk-shaped member having a predetermined thickness. Then, in a state where a part of the closing member 12 is inserted into one opening end of the housing 10, the peripheral wall of the housing 10 corresponding to the annular groove portion 13 provided on the peripheral surface of the closing member 12 is radially inward. The closing member 12 is caulked and fixed to the housing 10 by being reduced in diameter (caulked) and engaged with the annular groove 13.

  The holder 20 is made of a metal such as stainless steel, steel, an aluminum alloy, or a stainless alloy, and includes a cylindrical member having a hollow opening 21 extending in the same direction as the axial direction of the housing 10. An annular groove 23 for caulking and fixing described later is provided at a predetermined position. The annular groove 23 for fixing by caulking is formed on the outer peripheral surface of the holder 20 so as to extend in the circumferential direction. In the state where a part of the holder 20 is inserted into the other opening end of the housing 10, the peripheral wall of the housing 10 corresponding to the annular groove portion 23 provided on the outer peripheral surface of the holder 20 is contracted radially inward. The holder 20 is caulked and fixed to the housing 10 by engaging the annular groove 23 with a diameter (caulking).

  As shown in FIG. 1, an igniter 50 as a gas generating agent igniting means is disposed at one end of the housing 10 in the axial direction (that is, a portion near the holder 20). In addition, the holder 20 which fixes the igniter 50 and the igniter 50 has a function as an ignition means for generating a flame for burning a granular gas generating agent 30 which will be described later.

  The igniter 50 is inserted into the hollow opening 21 of the holder 20 and fixed by caulking. More specifically, the holder 20 has a caulking portion 20 a at an end portion facing the space inside the housing 10, and the igniter 50 is inserted into the hollow opening 21 and fixed to the holder 20. The igniter 50 is clamped by the holder 20 and the igniter 50 is fixed to the holder 20 by caulking the caulking portion 20a in the state of being done.

  More specifically, the igniter 50 includes a base frame for inserting and holding the pair of terminal pins 52, and a squib cup 50a attached on the base frame, and a terminal inserted into the squib cup 50a. A resistor (bridge wire) is attached so as to connect the tips of the pins 52, and an igniting agent is filled in the squib cup 50a so as to surround the resistor or in contact with the resistor. Nichrome wire or the like is generally used as the resistor, and ZPP (zirconium / potassium perchlorate), ZWPP (zirconium / tungsten / potassium perchlorate), lead tricinate, or the like is generally used as the igniting agent. In addition, the squib cup 50a may be filled with not only the igniting agent but also a propellant, but as the propellant that can be disposed simultaneously with the igniting agent, a metal / oxidant represented by boron / potassium nitrate or the like is used. And a composition composed of titanium hydride / potassium perchlorate, a composition composed of boron / 5-aminotetrazole / potassium nitrate / molybdenum trioxide, and the like. The squib cup is generally made of metal or plastic.

  When a collision is detected, a predetermined amount of current flows through the resistor via the terminal pin 52. When a predetermined amount of current flows through the resistor, Joule heat is generated in the resistor, and the ignition powder starts to burn upon receiving this heat. The high-temperature flame generated by the combustion ruptures the squib cup 50a containing the igniting agent. The time from when the current flows through the resistor until the igniter 50 is activated is 2 milliseconds or less when a nichrome wire is used as the resistor.

  As shown in FIG. 1, a working gas generation chamber 17 in which a gas generating agent 30 is accommodated, a filter chamber 18 in which a filter 40 is accommodated, and a winding spring 60 are accommodated in the internal space of the housing 10. An ignition chamber 19 is provided.

  As shown in FIG. 3A, the gas generating agent 30 has a through hole 30a provided along the axial direction and a plurality of groove portions 30b provided along the axial direction on the outer peripheral portion. It is a long cylindrical integral molded product that is ignited by a flame generated by being ignited by the igniter 50 and generates gas by burning. The gas generating agent 30 is generally formed as a molded body containing a fuel, an oxidant, and an additive. As the fuel, for example, a triazole derivative, a tetrazole derivative, a guanidine derivative, an azodicarbonamide derivative, a hydrazine derivative, or a combination thereof is used. Specifically, for example, nitroguanidine, guanidine nitrate, cyanoguanidine, 5-aminotetrazole and the like are preferably used. The oxidant was selected from basic nitrates such as basic copper nitrate, perchlorates such as ammonium perchlorate or potassium perchlorate, alkali metals, alkaline earth metals, transition metals, and ammonia. For example, nitrates containing cations are used. As the nitrate, for example, sodium nitrate, potassium nitrate and the like are preferably used. In addition, examples of the additive include a binder, a slag forming agent, and a combustion adjusting agent. As the binder, for example, a cellulose derivative such as hydroxypropylene methylcellulose, an organic binder such as a metal salt of carboxymethylcellulose, a stearate, an inorganic binder such as synthetic hydroxytalcite, and acid clay can be suitably used. As the slag forming agent, silicon nitride, silica, acid clay, etc. can be suitably used. Moreover, as a combustion regulator, a metal oxide, ferrosilicon, activated carbon, graphite, etc. can be used suitably. Here, for example, the composition of the gas generating agent 30 is guanidine nitrate / basic copper nitrate / potassium perchlorate, and guanidine nitrate / basic copper nitrate / potassium perchlorate constituting the gas generating agent 30 is formed. The case where the weight composition ratio is 55: 39: 6 in order is particularly preferable.

  As shown in FIG. 1, the filter chamber 18 communicates with the outside through the gas ejection port 11 provided on the peripheral wall of the housing 10 described above. In the filter chamber 18, a filter 40 made of a cylindrical member having a substantially columnar space 40a at the center is accommodated. In addition, when the filter 40 made of a cylindrical member is used in this way, the flow resistance of the working gas flowing through the filter chamber 18 during operation can be kept low, and an efficient gas flow can be realized. As the filter 40, for example, a wire made of a metal such as stainless steel or steel, a wire wound around a net, or a material pressed by pressing is used. Specifically, an aggregate of knitted wire mesh, plain weave wire mesh, or crimp-woven metal wire is used. The filter 40 functions as a cooling means for cooling the gas by taking away the high-temperature heat of the gas when the gas generated in the working gas generation chamber 17 passes through the filter 40 and is included in the gas. It also functions as a removing means for removing slag and the like. Here, as a modified example of the filter 40, a filter having a labyrinth channel formed by combining substantially cylindrical or mortar-shaped parts made of metal may be used. Thereby, since the course of working gas can be changed in various directions, it is possible to cool gas and remove slag.

  As shown in FIGS. 1A and 1B, the winding spring 60 has one end abutting against the holder 20 and the other end at least around the through hole on one end side of the gas generating agent 30. The gas generating agent 30 is provided so as to urge an elastic force in contact with a part thereof. By this urging, the gas generating agent 30 is fixed in the housing 10 so as to be sandwiched between the winding spring 60 and the filter 40. Further, as shown in FIGS. 2A and 2B, the winding spring 60 includes a large-diameter portion 60a that is densely wound and a reduced-diameter portion 60b that is loosely wound so as to have a predetermined interval. I have it. The winding pitch of the winding spring 60 is configured such that the large diameter portion 60a is smaller than the reduced diameter portion 60b. Here, the large diameter portion 60a is a portion that is spirally wound around the squib cup 50a along the inner wall of the housing 10, and when the winding spring 60 contracts, the large diameter portion 60a becomes the reduced diameter portion 60b. Further, the reduced diameter portion 60b is hardly deformed. Therefore, even if the reduced diameter portion 60b is mounted in the housing 10, it keeps a predetermined distance. Further, the reduced diameter portion 60b is wound so as to reduce the diameter in the direction from the boundary with the large diameter portion 60a toward the gas generating agent 30. Moreover, the top part of the reduced diameter part 60b is wound so that it may be located in the radial direction center part by the side of the one end part of the gas generating agent 30. FIG. Here, as a modification of the winding spring 60, as shown in FIG. 2C, a winding spring 70 having only a portion having the same shape as the reduced diameter portion 60b of the winding spring 60 can be cited.

  A female connector (not shown) is attached to the end of the gas generator 100 where the holder 20 is disposed. This female connector is a part to which a male connector of a harness that transmits a signal from a collision detection unit provided separately from the gas generator 100 is connected. A shorting clip (not shown) is attached to the female connector as necessary. The shorting clip is attached to prevent malfunction of the cylinder-type gas generator 100 due to electrostatic discharge or the like when the gas generator 100 is transported. When the male connector of the harness is inserted into the female connector, the contact with the terminal pin 52 is released.

  Next, the operation | movement at the time of the action | operation of the gas generator 100 demonstrated above is demonstrated. When a vehicle equipped with an airbag device incorporating the gas generator 100 according to the present embodiment collides, the collision is detected by a collision detection unit provided separately in the vehicle, and based on this, the igniter 50 is detected. Operates. When the igniter 50 is activated, the pressure in the igniter 50 increases due to the combustion of the igniting agent, thereby bursting the tip of the squib cup 50a of the igniter 50, and the flame is externally (ignited from the tip of the squib cup 50a of the igniter 50). Flows into chamber 19). Next, the flow path of the outflowed flame directly collides with the reduced diameter portion 60b of the winding spring 60 as shown by the thick arrow in FIG. The gas generating agent 30 is diverted into one that easily flows to the through hole 30a side and the one that flows toward the inner wall side of the housing and easily flows into the groove 30b of the gas generating agent 30. As a result, the flame diffuses, so that the flame is in wide contact with the surface of the gas generating agent 30, and the gas generating agent 30 is easily combusted. That is, since the contact area between the flame and the gas generating agent 30 becomes larger than before, the ignition efficiency of the gas generating agent 30 is improved.

  The gas generating agent 30 is ignited and burned by the flame that flows in this way, and a large amount of gas is generated. Due to the combustion of the gas generating agent 30, the pressure in the working gas generation chamber 17 rises, and the gas generated thereby flows into the filter chamber 18. The flowing gas is cooled to a predetermined temperature via the filter 40. A large amount of the cooled gas is ejected from the gas ejection port 11 to the outside of the gas generator 100. The gas ejected from the gas ejection port 11 is guided into the airbag to inflate and deploy the airbag.

(Main features of the gas generator 100)
According to the present embodiment, since the gas generating agent 30 can be pressed against the filter 40 by the winding spring 60, the cylindrical gas generating agent 30 in the working gas generating chamber 17 can be easily fixed in the housing 10. Can do. Further, the reduced diameter portion 60b of the winding spring 60 gradually decreases in diameter from the igniter 50 to the gas generating agent 30, and the winding interval of the reduced diameter portion 60b is a predetermined interval. The flow path of the generated flame is directly changed to the gas generating agent 30, changed to collide with the winding spring 60 and easily flows to the through hole 30 a of the gas generating agent 30, and on the inner wall side of the housing 10. It flows and is divided into those that are easy to flow into the groove 30b of the gas generating agent 30. As a result, the flame diffuses and easily comes into contact with the surface of the gas generating agent 30, and the ignition efficiency of the gas generating agent 30 is improved. For example, the gas generator 100 can be made smaller or longer than before. Even if it is made thin, the combustion performance of the gas generating agent 30 (for example, generating a predetermined amount of gas in a certain time) can be achieved as designed.

  In addition, since the outer diameter of the large diameter portion 60a formed continuously with the reduced diameter portion 60b is close to the inner diameter of the housing 10, the winding spring 60 is formed in comparison with the case where a winding spring having only the reduced diameter portion 60b is used. It can be fixed stably.

  Moreover, since the space | interval (pitch) of the large diameter part 60a is smaller than the space | interval of the reduced diameter part 60b in the winding spring 60, when the wound spring 60 contracts, the large diameter part 60a is larger than the reduced diameter part 60b. It deform | transforms previously, and the diameter reducing part 60b hardly deform | transforms. Therefore, even if the reduced diameter portion 60b is installed in the housing 10, it keeps a predetermined interval, so that the flame flow path of the igniter 50 does not change, and stable ignition is realized. Can do.

  Further, since the outer diameter of the gas generating agent 30 is substantially the same as the inner diameter of the housing 10, the gas generating agent 30 does not shift in the direction substantially perpendicular to the axis in the housing. The flame flow path may be as designed. Therefore, the combustion performance of the gas generating agent 30 can be achieved as designed.

  As mentioned above, although embodiment of this invention was described based on drawing, it should be thought that a specific structure is not limited to these embodiment. The scope of the present invention is shown not by the above description of the embodiments but by the scope of claims for patent, and further includes all modifications within the meaning and scope equivalent to the scope of claims for patent.

  For example, the gas generating agent 30 of the gas generator 100 of the above embodiment has an integrally formed long cylindrical shape having an outer diameter close to the size of the inner diameter of the housing 10. It is good also as a gas generating agent which arranged the gas generating agent of this short cylinder shape in the axial direction.

  Further, instead of the gas generating agent 30, a gas generating agent having a single-hole cylindrical shape as shown in FIG. 3B or 3C may be used. In other words, any through-hole may be provided as long as the winding spring 60 abuts and has an end capable of biasing the elastic force. For example, the gas generating agent 30 may be a molded body such as a porous cylinder having a plurality of holes inside.

  In addition, in the present embodiment, a configuration for particularly having the gas-tightness of the gas generator is not included, but a conventionally known member using an O-ring or an adhesive tape may be added as a matter of course.

  In the present embodiment, the closing member 12 is attached to the other end portion of the housing 10, but instead of the housing 10, the other end portion formed by deep drawing is a bottomed housing. It may be used.

  Further, in the present embodiment, the winding spring 60 whose one end is spirally wound around the inner wall of the housing 10 around the squib cup 50a is used. Instead, the squib cup of the igniter is used at one end. A large-diameter portion that is densely wound around and spirally wound around, and a reduced-diameter portion that is reduced in diameter from the large-diameter portion to one end portion of the gas generating agent and is loosely wound so as to leave a predetermined interval. A winding spring may be used. That is, at least one end portion (preferably, a large diameter portion of the winding spring) of the winding spring is wound around the squib cup of the igniter, so that the position of the winding spring can be further stabilized in the housing. . As a result, the flow path of the flame generated from the igniter can be made as designed, and the combustion performance of the gas generating agent can be achieved as designed.

DESCRIPTION OF SYMBOLS 10 Housing 11 Gas outlet 12 Closure member 13, 23 Annular groove part 17 Working gas production | generation chamber 18 Filter chamber 20 Holder 20a Caulking part 21 Hollow opening part 30 Gas generating agent 40 Filter 50 Igniter 52 Terminal pin 60, 70 Winding spring 100 Gas Generator

Claims (5)

Working gas in which a working gas is generated by burning a cylindrical gas generating agent having a through hole along the axial direction in the substantially central portion and at least one groove portion along the axial direction on the outer periphery. A long cylindrical housing containing therein a generation chamber and a filter chamber containing a filter through which the working gas generated in the working gas generation chamber passes;
A gas generating agent ignition means including an ignition agent, disposed at one end of the housing in the axial direction, and capable of igniting and burning the gas generating agent in the working gas generation chamber;
In the housing, one end is in contact with or attached to the gas generating agent ignition means, and at least a part of the other end is in contact with at least a part of the periphery of the through hole on one end side of the gas generating agent. A winding spring provided to bias the elastic force to the other end of the gas generating agent;
With
At least a part of the winding spring gradually decreases in diameter from the gas generating agent ignition means to the gas generating agent, and a winding interval of the reduced diameter portion is a predetermined interval,
The filter chamber is located on the other end side in the axial direction of the housing from the working gas generation chamber,
The peripheral wall portion of the portion defining the filter chamber of the housing is provided with a plurality of gas ejection ports for ejecting the working gas that has passed through the filter to the outside.
At least a part of the gas generating agent ignition means is covered with one end of the housing so that a gap between the gas generating agent ignition means and one end of the housing is closed, and the gas generating agent ignition means A gas generator fixed to the housing.   The gas generator according to claim 1, wherein the winding spring includes a large-diameter portion having a diameter larger than that of the reduced diameter portion in addition to the reduced diameter portion.   The gas generator according to claim 2, wherein an interval between windings of the large diameter portion is smaller than an interval between windings of the reduced diameter portion.   The gas generator according to claim 2 or 3, wherein the large-diameter portion of the winding spring is wound around at least a tip portion of the gas generating agent ignition means.   The gas generator according to any one of claims 1 to 4, wherein an outer diameter of the gas generating agent is substantially the same as an inner diameter of the housing.

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