JP2015013546A - Air bag inflator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the increase of a press-in load even if burrs and the like are engaged during pressing-in.SOLUTION: An inflator 11 includes: a pressure container 2; igniter portions 3 and 4; and gas generating agents 5a and 5b. The pressure container 2 has a base 2b joining adaptors 2ca and 2cb; and a diffuser 2a provided with a gas jetting hole 2aa. The igniter portions 3 and 4 have structures in which igniters 3a and 4a are stored in an igniter tube 7 and a 2nd cup 8 pressed in the adaptors 2ca and 2cb. The gas generating agents 5a nad 5b are stored in a gas generating agent filling portion enabling ignition from the igniter portions 3 and 4. On a contact surface in a press-in portion of the igniter tube 7 and the 2nd cup 8 into the adaptors 2ca and 2cb, a recessed portion 12 is formed. A press-in load is not increased, and the coating of lubricant to the contact surface in the press-in portion can be omitted.

Description

  The present invention relates to an inflator that generates gas to be supplied to an airbag installed in an automobile as a safety device.

  The airbag device protects an occupant from an impact during a collision by deploying the airbag with gas generated by an inflator.

  FIG. 4 is a central longitudinal sectional view for explaining an example of the structure of a dual stage type inflator. This inflator 1 includes first and second igniter portions 3 and 4 and first and second gas generations that are ignited by the first and second igniter portions 3 and 4 to generate gas. It is the structure which has arrange | positioned the filter 6 which adsorb | sucks the solid residue in generated gas 5a, 5b and the generated gas residue.

  Of these, the pressure vessel 2 is composed of a diffuser 2a and a base 2b connected to the diffuser 2a. A gas injection hole 2aa is formed on the side wall of the diffuser 2a, while two adapters are provided on the base 2b. 2ca and 2cb are joined.

  The first igniter 3 instantaneously converts the igniter 3a attached to the one adapter 2ca and the ignition energy of the igniter 3a into the igniter tube 7 fitted to the one adapter 2ca. It is the structure which accommodated the explosive charge 3b amplified in the.

  On the other hand, the 2nd igniter part 4 is the structure which accommodated the igniter 4a attached to the said other adapter 2cb in the inside of the 2nd cup 8 fitted to the said other adapter 2cb. The 2nd cup 8 is composed of a cap 8a having a through hole 8aa on the side wall and a tube 8b whose upper portion is covered with the cap 8a.

  The second gas generating agent 5 b is charged in a second gas generating agent filling portion inside the 2nd cup 8. The first gas generating agent 5 a is inserted into the first gas generating agent filling portion inside the first cup 9 inserted above the igniter tube 7 and outside the second cup 8. A through hole 9a is formed in the bottom wall of the 1st cup 9 to transmit the ignition of the charge transfer agent 3b to the first gas generating agent 5a.

  In the case of the inflator 1, when it is determined that the detected collision energy value is not too dangerous, only the igniter 3a of the first igniter unit 3 is operated to ignite the transfer charge 3b, and the through hole 9a of the 1st cup 9 is opened. The first gas generating agent 5a is ignited to generate gas. The generated gas is ejected from the gas ejection hole 2aa of the diffuser 2a through the filter 6 to deploy the airbag.

  On the other hand, when it is determined that the detected collision energy value is dangerous, the igniter 4a of the second igniter unit 4 is operated in addition to the igniter 3a of the first igniter unit 3 to generate the first and second gases. The agents 5a and 5b are ignited to generate a large amount of gas, and the airbag is deployed at a high speed.

  Note that the gas generated by the ignition of the second gas generating agent 5b reaches the first gas generating agent filling portion from the through hole 8aa of the cap 8a, and is ejected from the ejection hole 2aa of the diffuser 2a through the filter 6.

  4 in FIG. 4 is a glass fiber cushion member installed inside the ceiling wall of the diffuser 2a for the purpose of preventing the first gas generating agent 5a from moving due to vibration of the inflator 1 to prevent deformation and the like. .

  Incidentally, the igniter tube 7 and the 2nd cup 8 are generally attached to the adapters 2ca and 2cb in the inflator 1 by press-fitting (see, for example, the sixth line of paragraph 0033 of Patent Document 1).

  However, the press-fitting portions of the igniter tube 7 and the 2nd cup 8 to the adapters 2ca and 2cb are cylindrical surfaces as shown in FIG. Therefore, there is a problem that the press-fitting load becomes large when flash or the like generated by squeezing at the time of press-fitting is caught in the contact surface between the adapters 2ca and 2cb and the igniter tube 7 or the 2nd cup 8, so that the contact surface is lubricated. An agent is applied to prevent the press-fit load from increasing.

JP 2010-143270 A

  The problem to be solved by the present invention is that when the igniter tube or the 2nd cup is press-fitted into the adapter, if a flash generated by galling or the like bites into the contact surface between the adapter and the igniter tube or the 2nd cup, the press-fitting load Is that it becomes larger.

  The present invention prevents the press-fitting load from increasing even when a flash generated by galling or the like bites into the contact surface between the adapter and the igniter tube or 2nd cup when the igniter tube or 2nd cup is press-fitted into the adapter. It was made for the purpose.

In order to achieve the above object, the present invention provides:
An inflator for an airbag that generates gas for deploying an airbag,
Including a pressure vessel, an igniter, and a gas generating agent,
The pressure vessel has a base portion in which an adapter is joined to a base, and a diffuser portion that is joined to the base and has a gas ejection hole generated inside the inflator.
The igniter portion is configured such that an igniter is accommodated in an outer cylinder press-fitted into the adapter,
The gas generating agent is accommodated in a gas generating agent filling part in the pressure vessel capable of ignition from the igniter part,
The most important feature is that a concave portion is formed on the contact surface in the press-fitting portion of the outer cylinder to the adapter.

  Since the present invention forms a recess in the contact surface in the press-fitting portion of the outer cylinder to the adapter, even when a flash or the like generated by galling or the like bites into the contact surface when the outer cylinder is pressed into the adapter, It is possible to prevent the press-fit load from being increased by letting it escape to the recess. Further, since the contact area of the press-fit portion is reduced by the contact surface of the formed concave portion, the press-fit load is reduced.

  The concave portion can be simply formed by screw cutting. This recess is preferably formed only in either the adapter or the outer cylinder. The said outer cylinder means the cylindrical member hold | maintained at the outer peripheral part of an adapter, such as an igniter tube and the 2nd cup of a dual type inflator.

  In the present invention, when the outer cylinder is press-fitted into the adapter, even if a flash generated by galling or the like bites into the contact surface, the flash or the like is formed in the concave portion formed in the contact surface of the outer cylinder press-in portion to the adapter. Since it escapes, it can suppress that a press-fit load becomes large. Accordingly, the step of applying the lubricating oil to the contact surface in the press-fitting portion of the outer cylinder to the adapter can be omitted. Further, since the contact area of the press-fit portion is reduced by the contact surface of the formed concave portion, the press-fit load is reduced.

It is the figure which showed the dual stage type inflator of this invention, (a) is a center longitudinal cross-sectional view, (b) is the A section enlarged view of (a), (c) is the B section enlarged view of (a), d) It is the enlarged view which showed the other example of the A section of (a). It is the figure which showed the effect of the inflator of this invention. It is the figure which showed the single stage type inflator of this invention, (a) is a center longitudinal cross-sectional view, (b) is the C section enlarged view of (a). It is the figure which showed the conventional dual stage type inflator, (a) is a center longitudinal cross-sectional view, (b) is the D section enlarged view of (a), (c) is the E section enlarged view of (a).

  In the present invention, when the igniter tube or the 2nd cup or the like is pressed into the adapter, the press-fitting load does not increase even if a flash generated by galling or the like bites into the contact surface between the adapter and the igniter tube or the 2nd cup or the like. To achieve the goal of

  In the present invention, the above object is realized by forming a concave portion on a contact surface in a press-fitting portion such as an igniter tube or a 2nd cup to the adapter.

Hereinafter, an embodiment of the present invention will be described with reference to FIG.
FIG. 1 is a view showing a dual stage type inflator of the present invention.

  The inflator 11 of the present invention includes first and second gas generating agents 5a that generate gas by ignition in the first and second igniter portions 3 and 4 and the igniter portions 3 and 4 inside the pressure vessel 2. , 5b and the filter 6 are accommodated.

  Among these, the pressure vessel 2 has a base part and a diffuser part joined to the base part. Among these, the base portion is configured by joining two adapters 2ca and 2cb to the base 2b, and the diffuser portion is configured by providing a gas ejection hole 2aa generated inside the inflator 11 on the side wall of the diffuser 2a. It is.

  The first igniter unit 3 includes an igniter tube in which an igniter 3a installed in the one adapter 2ca and a transfer agent 3b that instantaneously amplifies the ignition energy of the igniter 3a are press-fitted into the one adapter 2ca. 7 is housed inside. The explosive charge 3b is inserted below the 1st cup 9 which has been inserted into the igniter tube 7 from above the igniter tube 7 and has a through hole 9a in the bottom wall.

  On the other hand, the second igniter section 4 includes a 2nd cup 8 comprising a cap 8a having a through-hole 8aa formed in a side wall and a tube 8b in which an igniter 4a installed in the other adapter 2cb is press-fitted into the other adapter 2cb. It is the structure accommodated in the inside.

  The first and second gas generating agents 5a and 5b are accommodated in a gas generating agent filling portion in the pressure vessel 2 that can be ignited from the first and second igniter portions 3 and 4. Yes.

  Specifically, the second gas generating agent 5 b is charged in a second gas generating agent filling portion inside the 2nd cup 8. The first gas generating agent 5 a is inserted into the first gas generating agent filling portion inside the first cup 9 inserted above the igniter tube 7 and the outer peripheral portion of the second cup 8.

  A cushion member 10 is installed on the inside of the ceiling wall of the diffuser 2a in the first gas generating agent filling portion in order to prevent the first gas generating agent 5a from moving due to the vibration of the inflator 11 to prevent deformation or the like. Yes.

  In the inflator 11 shown in FIG. 1, a recess 12 is formed on the contact surface at the press-fitting portion of one adapter 2ca, the igniter tube 7 press-fitted into this adapter, and the other adapter 2cb and the 2nd cup 8 press-fitted into this. doing. The recess 12 is formed on the surfaces of one adapter 2ca and the other adapter 2cb.

  The concave portion 12 can be of any size, cross-sectional shape, and pitch as long as it can release the flashing bite on the contact surface when the igniter tube 7 or the 2nd cup 8 is pressed into the adapters 2ca and 2cb. .

  For example, in the inflator 11 shown in FIG. 1, the sawtooth-shaped recessed part 12 is helically formed on the surface of the contact surface at the time of press-fitting of the adapters 2ca and 2cb. On the surface of the contact surface of the igniter tube 7 or the 2nd cup 8, a saw blade-like recess 12 may be formed in a spiral shape. The cross-sectional shape of the recess 12 is not limited to a saw blade shape, and may be a rectangular shape or the like. Further, a plurality of discontinuous recesses 12 may be formed in parallel even if they are not continuous in a spiral shape. The saw-tooth-shaped recess 12 may be simply formed by screw cutting.

  In the present invention, when the igniter tube 7 and the 2nd cup 8 are press-fitted into the adapters 2ca and 2cb, even if a flash generated by galling or the like is caught in the contact surface, the flash or the like can be released to the recess 12. it can.

  Therefore, the press-fitting load of the igniter tube 7 and the 2nd cup 8 to the adapters 2ca and 2cb does not increase, and lubricating oil is applied to the contact surface at the press-fitting portion of the igniter tube 7 and the 2nd cup 8 to the adapters 2ca and 2cb. The process can be omitted. In addition, since the contact area of the press-fit portion is reduced by the contact surface of the formed recess 12, the press-fit load is reduced.

  Incidentally, as in the inflator 11 shown in FIG. 1, FIG. 2 shows a measurement of the relationship between the press-fitting stroke and the press-fitting load when the recesses 12 are formed in the adapters 2 ca and 2 cb and when the recesses 12 are not formed. .

  FIG. 2 is a diagram showing the measurement results when the igniter tube 7 is pressed into the adapter 2ca four times, and the press-fitted portion has an inner diameter of 16.38 mm and an outer diameter of 16.56 mm, and is formed in the press-fitted portion. The concave portion 12 is thread-cut into a saw blade shape having a depth of 0.2 mm and a pitch of 0.25 mm.

  As shown in FIG. 2, the press-fitting load when the press-fitting stroke is 3.5 mm is 6.9 to 7.6 kN in the conventional example in which the concave portion 12 is not formed, but in the present invention example in which the concave portion 12 is formed. 3.1 to 4.4 kN.

  According to the experiments by the inventors, when the sawtooth-shaped recess 12 is formed in each of the adapters 2ca and 2cb, the pitch is preferably in the range of 0.2 mm to 0.35 mm.

  This is because if the pitch is less than 0.2 mm, the space of the concave portion 12 becomes narrow and it becomes impossible to release the bite. On the other hand, if the pitch exceeds 0.35 mm, it is possible to release the bite and the like, but the press-fit load becomes too small and it is easy to come off.

  The present invention is not limited to the above examples, and it goes without saying that the embodiments may be appropriately changed as long as they are included in the scope of the technical idea described in each claim.

  That is, the airbag inflator described above is a preferred example of the present invention, and other embodiments can be implemented or performed by various methods. In particular, the present invention is not limited to the detailed shape, size, configuration, and the like of the components shown in the accompanying drawings unless otherwise specified in the present specification. In addition, expressions and terms used in the present specification are for the purpose of explanation, and are not limited thereto unless specifically limited.

  Burst is most likely to occur at the beginning of press-fitting. This is because, at the start of press-fitting, the axis centers of the adapters 2ca and 2cb and the igniter tube 7 and the second cup 8 are not yet completely coincident with each other, and the contact surfaces of the press-fitting portions are not in contact with each other. Therefore, as shown in FIGS. 1A to 1C, the concave portion 12 is not formed over the entire contact surface of the press-fitting, but only at the press-fitting start side portion as shown in FIG. The recess 12 may be formed. By forming the concave portion 12 only in the press-fitting start side portion and letting the flash generated in the initial press-fitting to the concave portion 12, an effect of reducing the press-fitting load can be expected.

  Moreover, although the method to form the recessed part 12 by screw cutting was disclosed, you may form by the method of roughening the surface with sandpaper etc. by forming by knurling. When roughening, the value of Ra (arithmetic mean roughness, defined in JIS B 0601 (1994), JIS B 0031 (1994), etc.) is preferably about 40 to 70.

  Further, in the example shown in FIG. 1, the second igniter unit 4 is not charged with the explosive charge. However, like the first igniter unit 3, the second igniter unit 4 is also transferred into the 2nd cup 8. You may charge gunpowder. On the other hand, as long as the first gas generating agent 5 a can be ignited even without the transfer agent, the first igniter unit 3 may omit the transfer agent as with the second igniter unit 4.

  Furthermore, in the example shown in FIG. 1, the recess 12 is formed only in the adapters 2 ca and 2 cb, but the recess 12 may be formed only in the igniter tube 7 and the 2nd cup 8. If the holding strength of the igniter tube 7 and the 2nd cup 8 can be ensured, the recesses 12 may be formed in both the adapters 2ca and 2cb and the igniter tube 7 and the 2nd cup 8.

  1 describes the dual-stage type inflator 11, the present invention can also be applied to the single-stage type inflator 21 shown in FIG. In FIG. 3, the same reference numerals as those in FIG. 1 denote the same members, and detailed description thereof is omitted.

  The single stage type inflator 21 is obtained by omitting the other adapter 2cb, the second igniter section 4, the second gas generating agent 5b, and the 2nd cap 8 in the dual stage type inflator 11 shown in FIG. .

  And one adapter 2ca and the 1st igniter part 3 are arrange | positioned in the axial center part of the pressure vessel 2, and the 1st gas generating agent 5a is arrange | positioned in the outer peripheral part of the igniter tube 7 press-fit in one adapter 2ca It is. In this case, the first gas generating agent 5 a is ignited through the through hole 7 a formed in the side wall of the igniter tube 7.

  In the example shown in FIG. 3, not only between the retainer disk 22 fitted into the upper end of the igniter tube 7 and the first gas generating agent 5a, but also between the base 2b and the first gas generating agent 5a. A cushion member 10 is installed.

2 pressure vessel 2a diffuser 2aa ejection hole 2b base 2ca one adapter 2cb other adapter 3 first igniter 3a igniter 4 second igniter 4a igniter 5a first gas generating agent 5b second gas generating agent 6 Filter 7 Igniter tube 8 2nd cup 11 Inflator 12 Recess 21 Inflator

Claims (10)

An inflator for an airbag that generates gas for deploying an airbag,
Including a pressure vessel, an igniter, and a gas generating agent,
The pressure vessel has a base portion in which an adapter is joined to a base, and a diffuser portion that is joined to the base and has a gas ejection hole generated inside the inflator.
The igniter portion is configured such that an igniter is accommodated in an outer cylinder press-fitted into the adapter,
The gas generating agent is accommodated in a gas generating agent filling part in the pressure vessel capable of ignition from the igniter part,
An inflator for an air bag, wherein a concave portion is formed on a contact surface in a press-fitting portion of an outer cylinder to the adapter.   The airbag inflator according to claim 1, wherein the recess is formed in either the adapter or the outer cylinder.   The airbag inflator according to claim 1, wherein the concave portion is formed in both the adapter and the outer cylinder.   The airbag inflator according to any one of claims 1 to 3, wherein the concave portion is formed only in the vicinity of a press-fitting start portion of the press-fitting portion.   The airbag inflator according to any one of claims 1 to 4, wherein the concave portion is a sawtooth spiral groove.   6. The airbag inflator according to claim 5, wherein the sawtooth spiral groove is formed by thread cutting.   The airbag inflator according to claim 5 or 6, wherein a pitch of the sawtooth spiral groove is 0.2 mm or more and 0.35 mm or less.   The inflator for an air bag according to any one of claims 1 to 7, wherein the outer cylinder is an igniter tube.   The inflator for an air bag according to any one of claims 1 to 7, wherein the outer cylinder is an igniter tube and a 2nd cup.   The airbag according to any one of claims 1 to 9, further comprising a filter provided along an inner surface of a side wall of the pressure vessel between the pressure vessel and the gas generant filling portion. For inflator.

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