JP2003025950A - Gas generator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gas generator with a low manufacturing cost and high reliability used for a seat belt pre-tensioner, etc. SOLUTION: The gas generator is provided with a cup body filled with a gas generation agent for generating a gas by burning; an igniter for igniting the gas generation agent by an energization; and a support for supporting the igniter from an opposite side to the cup body. The igniter confines the gas generation agent in the cup body and is clamped by the cup body and the support.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a gas generator, and more particularly to a gas generator suitable for operating a seat belt pretensioner of an automobile.

[0002]

2. Description of the Related Art A seat belt pretensioner is known as one of safety devices for protecting an occupant from an impact generated when a vehicle crashes. This pretensioner operates by a large amount of high temperature and high pressure gas introduced from a gas generator to protect an occupant. This gas generator includes an igniter and a gas generating agent, and ignites and burns the gas generating agent at the time of collision to rapidly generate a large amount of gas. However, as this type of gas generator, various types have been proposed and realized, but they are much smaller than the gas generator for an airbag, and unexpectedly, there are cases in which there is difficulty in manufacturing. there were.

[0003]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a gas generator used in a seat belt pretensioner or the like, which has low manufacturing cost and high reliability.

[0004]

DISCLOSURE OF THE INVENTION The inventor of the present invention has a cup body in which a gas generating agent for generating gas by combustion is loaded, the gas generating agent is sealed in the cup body, and the gas generating agent is ignited by energization. In a gas generator including an igniter and a support body that supports the igniter from the side opposite to the cup body, sandwiching the igniter between the cup body and the support body The present invention has been found to solve the above problems, and has led to the present invention. That is, the present invention is
(1) A cup body that is loaded with a gas generating agent that generates gas by combustion, an igniter that ignites the gas generating agent by energization, and a support body that supports the igniter from the side opposite to the cup body, A gas generator, wherein the igniter seals the gas generating agent in the cup body and is sandwiched between the cup body and the support body; ) The gas generator according to (1), wherein the support is welded to the cup body at its opening and is fixed to the cup body, (3).
The gas generator according to (2), wherein the welding of the cup body and the support body is performed by separating the igniter from the gas generating agent, (4) the opening portion of the support body is the cup. The gas generator according to any one of (1) to (3), which is extended to reach the bottom of the body, and (5) the igniter is molded by injection molding an insulating member. (1) The gas generator according to any one of (1) to (4), (6) the support is provided with a hole for passing an electrode pin for energizing the igniter. The gas generator according to any one of (1) to (5), characterized in that a reinforcing material having a diameter larger than the hole is insert-molded, (7) the igniter is Provided along the inside of the cup body with an annular protrusion protruding toward the gas generating agent. The gas generator according to any one of (1) to (6), and (8) a seal member is arranged between the support and the igniter. (1) A gas generator according to any one of (1) to (7), (9) a gap is provided in a part between the igniter and the support, and the cup body is fitted into the gap. (1) The inserted gas generator according to any one of (1) to (8), (10) the axial length of the gap is ⅓ of the length of the protrusion on the gas generating agent side of the igniter. (2) the gas generator according to (9), (11) the cup body in which the gas generating agent is weighed, the opening of the cup body is directed substantially upward, and the igniter is covered from above. Next, the cup body is rotated to make the opening of the cup body substantially downward, and the cup body is completely inserted and fixed. 1) (10)
(12) A method for manufacturing a gas generator according to any one of
An occupant restraining seat belt retractor using the gas generator according to any one of (1) to (10), (13)
An airbag inflator using the gas generator according to any one of (1) to (10) as an igniter.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION A gas generator according to an embodiment of the present invention will be described with reference to the drawings.

A gas generator 1 shown in FIG. 1 is for operating a seat belt pretensioner of an automobile, and burns a gas generating agent by ignition of an igniter to rapidly generate a large amount of gas. Is.

The gas generator 1 has a bottomed cylindrical cup body 3 in which a gas generating agent 2 for generating gas by combustion is loaded.
And an igniter 5 that ignites the gas generating agent 2 by energization, and a support 4 that contains and supports the igniter 5 and into which the cup body 3 is fitted. The igniter 5 is attached to the cup body 3. While being fitted and sealing the gas generating agent 2 in the cup body 3, the gas generating agent 2 is fixed so as to be sandwiched between the support body 4 and the cup body 3.

The cup body 3 is formed in a cylindrical shape with a bottom,
A gas generating agent 2 that generates gas by combustion is loaded. A plurality of notches 3b are formed in the cup bottom 3a of the cup body 3, and the notches 3b partially cover the cup bottom 3a due to an increase in internal pressure of the cup body 3 due to combustion of the gas generating agent 2. By bending, a gas discharge hole is formed so that the inside of the cup body 3 communicates with the outside. An igniter 5 is fitted in the opening 3c of the cup body 3, the gas generating agent 2 in the cup body 3 is sealed, and a combustion chamber S is formed. The diameter of the side tubular portion of the cup body 3 is substantially the same from the cup bottom 3a to the opening 3c.

The igniter 5 which is fitted into the cup body 3 and seals the gas generating agent 2 in the cup body 3 comprises a squib 6 and a molded body 7 made of an insulating member such as resin. It has a substantially cylindrical shape. Further, the molded body 7 includes
The reinforcing material 8 is provided mainly for the purpose of improving the strength of the molded body 7. Such an igniter 5 is injection-molded by an insulating member, and is integrated by insert-molding the squib 6 and the reinforcing material 8 at the time of injection molding. The reinforcing member 8 integrated with the igniter is made of a member having higher strength than the molded body 7, for example, a metal member. Further, the shape is not particularly limited, and the strength of the molded body 7 and hence the strength of the igniter 5 is improved (for example, due to thermal expansion of the insulating member (molded body 7) in the operation of the gas generator 1) The gas generator 1 has a hollow disk-shaped ring shape, and the ring portion is further provided with a plurality of holes. Since the holes are filled with the insulating member of the molded body 7, the reinforcing material 8 is more firmly fixed to the molded body 7. Further, the hollow portion of the reinforcing member has a diameter such that the electrode pin 6a of the squib 6 does not come into contact with the hollow portion,
In addition, the diameter of the squib 6 is smaller than the diameter of the main body of the squib 6, so that the squib 6 is not short-circuited and the pressure of the squib 6 causes the gas generator 1 to operate when the gas generator 1 operates. Prevent it from jumping out. One end 5a (the end opposite to the gas generating agent 2) of the igniter 5 is a tubular portion 10, and a plug fitting hole into which a plug (not shown) is fitted is provided on the inner peripheral side of the tubular portion 10. Is formed, and the two electrode pins 6a of the squib 6 project into the plug mounting hole. The electrode pin 6a is a shorting clip that prevents malfunction due to static electricity until it is incorporated into a seat belt pretensioner or the like. 1
2 is attached. Also, the other end 5b of the igniter 5
An annular protrusion 9 is formed on the (gas generating agent 2 side) so as to protrude along the inner circumference of the cup body 3. Further, on the outer periphery of the igniter 5, a stepped portion 5c corresponding to the thickness of the tubular portion of the cup body 3 is provided.
The diameter from the stepped portion 5c to the one end 5a is substantially the same as the inner diameter of the tubular portion of the support body 4. On the other hand, the diameter from the stepped portion 5c to the other end 5b (annular protrusion 9) is substantially the same as the inner diameter of the tubular portion of the cup body, and the cup body 3 is inserted between the support body 4 and the support body 4. The cup body fitting insertion groove 13 is formed. The width of the cup body fitting groove 13 is substantially the same as the thickness of the tubular portion of the cup body 3. Then, the igniter 5 is inserted into the cup body 3 from the annular projection 9 so that the squib 6 faces the gas generating agent 2, and the opening 3c of the cup body 3 contacts the stepped portion 5c of the igniter 5. Contacted and positioned.

A substantially cylindrical support 4 for supporting the igniter 5.
Has its one end 4a abutted on the reinforcing member 8 exposed at the root of the cylindrical portion 10 of the igniter 5 on the inner peripheral side to form a hole for passing the electrode pin 6a of the squib 6. Further, while forming the bag-shaped portion 4b following the shape of the tubular portion 10, the one end 5a of the igniter 5 to the cup bottom 3a of the cup body 3 is formed.
Until they reach the same diameter. On the way
From the stepped portion 5c of the igniter 5 to the annular projection 9, a gap is formed as a cup body fitting groove 13 between the igniter 5 and the support body 4, and the cup body fitting groove 13 has a gap. The openings 3c of 3 are inserted. As described above, since the outer diameter of the hollow disk-shaped reinforcing member 8 is larger than the inner diameter of the support 4 on the side of the one end 4a, the igniter 5 is activated by pressure and heat during operation of the gas generator 1. Even if the molded body 7 is softened or weakened, the integrated reinforcing member 8 is always engaged with the support body 4, and the igniter 5 can be prevented from jumping out from the gas generator 1. Then, in the opening 4c of the support body 4 near the cup bottom 3a, welding is performed along the circumference 14 that overlaps with the cup body 3, whereby the igniter 5 is sandwiched between the cup body 3 and the support body 4. -It is fixed and secures airtightness between the cup body 3 and the support body 4. Further, a seal member 11 is arranged between the one end 5 a of the igniter 5 (the tip of the tubular portion 10) and the support body 4, and seals between the inner circumference of the support body 4 and the igniter 5. .

Here, it is preferable that both the support 4 and the cup 3 are made of a weldable material, for example,
It is preferable to use a metal material such as iron, aluminum, brass, and stainless steel, but the materials for the support 4 and the cup 3 are not necessarily the same.

Next, a method of manufacturing the gas generator of the present invention will be described with reference to FIG. 2 by taking the manufacturing process of the gas generator 1 shown in FIG. 1 as an example.

First, a method of forming the igniter 5 will be described. A resin (for example, polybutylene terephthalate, polyethylene terephthalate, nylon 6, nylon 66, etc.) that serves as an insulating material used for molding the molded body 7 of the igniter 5.
A resin such as polypropylene sulfide or polypropylene oxide containing glass fiber or the like) is injected into a molding die (not shown) for molding. At this time, the respective constituent parts (squib 6, reinforcement 8, etc.) included in the igniter 5 are arranged in advance in the mold and integrated by injection molding.

Next, the igniter 5 is inserted into the support body 4. At this time, the seal member 11 is arranged on the inner circumference of the bag-shaped portion 4b of the support body 4, and by inserting the igniter 5, the seal member becomes the bag-shaped portion 4b and the tubular portion 10 of the igniter 5. It is supported in the form of being sandwiched by. Seal member 1
Reference numeral 1 denotes a role of preventing entry of moisture and the like, and an O-ring, a sheet packing or the like molded of rubber or the like is preferable. Also,
Silicon or the like dispersed in a solvent may be applied. (Fig. 2
(See (a)) Then, the shorting clip 12 is attached to the plug fitting hole on the inner peripheral side of the tubular portion 10 of the igniter 5.

Next, the cup body 3 loaded with the measured gas generating agent 2 is set so that the opening 3c faces upward (so that the gas generating agent 2 does not spill), and the igniter 5 is inserted. The supporting body 4 is covered over the cup body 3 from above. At this time, the opening 3c of the cup body 3 is not
Is inserted along the inner periphery of the cup body, and is further fitted into the cup body fitting groove 13 between the igniter 5 and the support body 4. (Fig. 2 (b)
Then, when the opening 3c of the cup body 3 reaches the outer circumference of the annular projection 9 of the igniter 5, these are rotated by 180 ° (upside down) and the opening 3c of the cup body 3 is directed downward. At this time, the gas generating agent 2 is supplied to the squib 6 of the igniter 5.
Is filled without a gap between the periphery of the gas generating agent 2 and the annular projection 9, and a chemical surface of the gas generating agent 2 becomes a flat surface in the upper portion (near the cup bottom 3a) of the cup body 3 to form a gap. (See FIG. 2C) Then, the insertion of the cup body 3 into the igniter 5 and the support body 4 is restarted, and the cup body 3 is fitted between the annular projection 9 of the igniter 5 and the support body 4, The opening 3c is brought into contact with the stepped portion 5c of the igniter 5 for positioning. As a result, the gas generating agent loading space (maximum packing density) with no gap is completed in the combustion chamber S in the cup body 3. At this time, since the diameter of the side tubular portion of the cup body 3 is substantially the same from the cup bottom 3a to the opening 3c, there is no fear of crushing the gas generating agent 2 when the cup body 3 is fitted.

At this time, the length Ls of the cup body fitting groove 13, that is, the length Ls from the stepped portion 5c to the tip of the annular projection 9 which is the end of the igniter 5 is the gas generating agent 2 of the igniter 5. Side projection length, that is, 1/3 to 2 times the length Li from the other end 5b of the igniter to the tip of the squib 6, so that the gas generator is turned upside down as described above. During production, the gas generant does not dissipate outside the gas generator.

Next, the opening 4c of the support body and the cup body are welded along the circumference 14 where they overlap to seal the gas generating agent 2 and the igniter 5 inside the cup body 3,
Fix it. (See Fig. 2 (d))

Next, the operation of the gas generator 1 of the present invention will be described. In the gas generator 1, when the electrode pin 6a of the squib 6 is energized, the squib 6 is ignited, and the ejected flame causes the gas generant 2 to start burning and to start releasing gas. Eventually, the notch 3b of the cup body 3 is broken by the pressure inside the cup body 3, and a large amount of gas is introduced into a seat belt pretensioner (not shown). And
The high pressure gas actuates the seat belt pretensioner to tighten the seat belt.

The gas generator 1 of the present invention has the above-mentioned structure. However, since the igniter 5 is fixed so as to be sandwiched between the support body 4 and the cup body 3, the gas generator 1 of the conventional gas generator is fixed. It has a simpler structure and can be easily manufactured. Further, since the support body 4 and the cup body 3 are fixed by welding, as compared with the gas generator which is fixed by caulking in the related art, the sealing property against infiltration of moisture is high.
As a result, the manufacturing process can be simplified and the reliability against moisture intrusion can be improved. In addition, the opening 4c of the support 4
Is extended to reach the cup bottom 3a of the cup body 3, the cup body 3 may have the same thickness (strength) from the cup bottom 3a to the side tube portion and the opening 3c. Since the portion excluding 3a can be supported by the support 4, even if the notch 3b or the like is not provided, only the cup bottom 3a can be reliably broken when the gas generator 1 is operated, and the gas can be appropriately released.

Next, a gas generator according to another embodiment of the present invention will be described with reference to FIG.

In the gas generator 21 shown in FIG.
The difference from the gas generator 1 shown in (1) is that the welding position between the support 4 and the cup body 3 is not near the cup bottom 3a of the cup body 3 but near the opening 3c. Other points are shown in Figure 1.
Since it is the same as that of the gas generator 1, the same reference numerals are given and detailed description thereof is omitted.

The opening 4c of the support body 4 is located in the cup body fitting groove 13 which is a gap between the igniter 5 and the support body 4 between the stepped portion 5c of the igniter 5 and the annular projection 9. There is. The opening 4c is welded to the cup body 3 so that the igniter 5 is sandwiched between the cup body 3 and the support body 4.
While being fixed, the airtightness between the cup body 3 and the support body 4 is secured.

In the gas generator 21, the cup body 3 and the support body 4 are welded to each other with the molded body 7 of the igniter 5 separated from the gas generant 2, so that the heat of welding is transmitted to the gas generant 2. Can be effectively prevented.

Next, a gas generator according to still another embodiment of the present invention will be described with reference to FIG.

In the gas generator 31 shown in FIG.
The difference from the gas generator 1 shown in (1) is that the squib 6 of the igniter 5 is integrally formed with the molded body 7 in common. Since the other points are the same as those of the gas generator 1 of FIG. 1, the same reference numerals are given and detailed description thereof will be omitted.

The squib 6 has two electrode pins 6a and two electrode pins 6 which axially penetrate the molded body 7 having a substantially cylindrical shape.
A bridge line 6b connecting the gas generating agent 2 side of a and a bridge line 6
It is composed of an ignition ball 6c which is constructed in b and is ignited by the Joule heat of the bridge wire 6b, an igniting agent 6d which is in contact with the ignition ball 6c, and a tube body 6e which seals these in a molded body 7. That is, the molded body 7 plays a role of an embolus for sealing the ignition ball 6c and the ignition charge 6d in the tube body 6e, and the squib 6 shares some of its constituent members with the molded body 7 while the igniter 5 is configured. Has been done.

The manufacturing of such an igniter 5 is carried out by using the electrode pin 6
After arranging a in the mold, the insulating material is injected to first obtain a molded body 7 provided with electrode pins 6a, and subsequently, bridge wires 6b are connected between the electrode pins 6a to form bridge wires 6b. Ignition ball 6
The squib 6 is constructed by constructing c and fitting the tubular body 6e filled with the ignition charge 6d so that the ignition ball 6c contacts the ignition charge 6d. In addition, the gas generator 3 of FIG.
In No. 1, the electrode pin 6a has a curved portion that curves in the molded body 7, and the distance between the curved portions is set to be larger than the inner diameter of the hollow disk-shaped reinforcing member 8. As a result, when the gas generator operates, the inside of the tube body 6e or the cup body 3 is
It is possible to prevent the electrode pin 6a from penetrating the support 4 and jumping out of the gas generator 31 due to the internal pressure.

The gas generators 1 and 2 shown in FIGS.
In 1 and 31, the igniter integrated with the squib is used, but the squib may be attached to the lid member that seals the gas generating agent in the cup body, and both may be combined to form the igniter used in the present invention. . In this case, it is preferable that a seal member is provided between the lid member and the squib so as to maintain airtightness. Further, the fixing of the cup body and the support body is not limited to welding, as long as it is a fixing method such as caulking, a screw, etc., which can obtain a necessary and sufficient fixing strength,
Can be adopted.

[0029]

According to the gas generator of the present invention, since the igniter is sandwiched and fixed by the support and the cup body, the number of steps can be reduced. In addition, since the support body and the cup body are joined by welding, the reliability with respect to intrusion of moisture or the like from the outside becomes high. Also, the igniter has
By insert-molding the reinforcing material together, deformation due to thermal expansion of the insulating member during operation of the gas generator is suppressed and strength is improved. Therefore, when an external fire or the like occurs, it is possible to prevent scattered substances from the inside of the gas generator. Also, by providing an annular protrusion on the igniter,
It has the effects of improving the gas generant loading rate and preventing ignition of the gas generant during welding.

[Brief description of drawings]

FIG. 1 is a schematic sectional view of an example of a gas generator according to the present invention.

FIG. 2 is a schematic view of a method for manufacturing the gas generator shown in FIG.

FIG. 3 is a schematic sectional view of an example of a gas generator according to the present invention.

FIG. 4 is a schematic sectional view of an example of a gas generator according to the present invention.

[Explanation of symbols]

1, 21, 31 gas generator 2 gas generating agents 3 cups 3a cup bottom 3b cutout 3c opening 4 support 4a one end 4b bag-shaped part 4c opening 5 igniter 5a one end 5b other end 5c Stepped part 6 squibs 6a Electrode pin 6b Denbashi Line 6c ignition ball 6d ignition powder 6e tube 7 molded 8 Reinforcement material 9 annular protrusion 11 Seal member 12 Shorting clips 13 Cup body insertion slot Li igniter protrusion length Ls Length of cup body fitting groove S combustion chamber

Claims (13)

[Claims] 1. A cup body loaded with a gas generating agent for generating gas by combustion, an igniter for igniting the gas generating agent by energization, and a support for supporting the igniter from a side opposite to the cup body. And a gas generator, wherein the igniter seals the gas generating agent in the cup body,
A gas generator, which is sandwiched between the cup body and the support body. 2. The gas generator according to claim 1, wherein the support is welded to the cup body at its opening and is fixed to the cup body. 3. The gas generator according to claim 2, wherein the welding of the cup body and the support body is performed by separating the igniter from the gas generating agent. 4. The gas generator according to claim 1, wherein the opening of the support extends to the bottom of the cup. 5. The gas generator according to claim 1, wherein the igniter is molded by injection molding an insulating member. 6. The support is provided with a hole for passing an electrode pin for energizing the igniter,
The gas generator according to any one of claims 1 to 5, wherein a reinforcing material having a diameter larger than the hole is insert-molded. 7. The igniter according to claim 1, wherein an annular projection is provided along the inside of the cup body so as to project toward the gas generating agent. Gas generator. 8. The gas generator according to claim 1, further comprising a seal member disposed between the support and the igniter. 9. The gas according to claim 1, wherein a gap is provided in a part between the igniter and the support, and the cup body is fitted in the gap. Generator. 10. The gas generator according to claim 9, wherein the axial length of the air gap is 1/3 to 2 times the length of the gas generating agent side protrusion of the igniter. . 11. A cup body in which a gas generating agent is weighed, the opening portion of which is directed substantially upward, an igniter is covered from above, and then the cup member is rotated so that the opening portion of the cup member is directed substantially downward so that the cup body is completely closed. The method for manufacturing a gas generator according to any one of claims 1 to 10, wherein the gas generator is inserted into and fixed to the gas generator. 12. A seat belt retractor for restraining an occupant, which uses the gas generator according to any one of claims 1 to 10. 13. An airbag inflator using the gas generator according to claim 1 as an igniter.