JPH0637015U - Inflator for airbag device - Google Patents

Abstract

(57) [Summary] [Objective] It is an object to obtain an inflator for an airbag device, which can secure sufficient joint strength and can improve reliability for welding. The inflator 10 includes an inner cylinder including an inner cylinder body 30 and an inner cylinder lid 32, an intermediate cylinder including an intermediate cylinder body 56 and an intermediate cylinder lid 58, and an outer cylinder including an upper outer cylinder 68 and a lower outer cylinder 70. The flare part (P1)
The flare portion (P7) is joined to each other by flare joint welding using a laser beam or an electron beam. Therefore, since the welding area can be sufficiently secured, sufficient joint strength can be secured and the reliability for welding can be improved.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an inflator for an airbag device that ejects gas when a vehicle is suddenly decelerated to inflate a bag toward an occupant.

[0002]

[Prior art]

 In an air bag device, for example, an air bag device installed on the driver's side, a large amount of gas is generated from a hollow columnar inflator due to the activation of a sensor when the vehicle decelerates rapidly. It is configured to bulge toward. Although there are various structures of the inflator of such an airbag device, an inflator having a can structure formed by appropriately welding a plurality of bottomed cylinders among them has already been devised by the applicant (one example). See Jpn. Pat. Appln. No. 4-64877). The structure will be briefly described below.

As shown in FIG. 3, in the inflator 100, an inner cylinder 102 having a bottomed cylindrical shape, an annular outer cylinder 104 arranged on an outer peripheral portion of the inner cylinder 102, an inner cylinder 102 and an outer cylinder. A large-diameter cylindrical body 106 that accommodates a half of the cylinder 104 on the occupant side and has a larger diameter than the outer diameter of the outer cylinder 104, and an inner cylinder 102 and an outer cylinder 104 that are fitted to the large-diameter cylindrical body 106 from the occupant side. And a closed cylindrical body 108 for accommodating the half on the side opposite to the occupant.

The inner cylinder 102 accommodates a mechanical ignition type sensor 110 for detecting a sudden deceleration state of the vehicle, a pair of detonators (ignition agent) 112, and an enhancer (transfer agent) 114. In addition, a gas generating agent 116 that combusts through the enhancer 114 to generate a large amount of gas when the detonator 112 ignites, and the first coolant 118 that cools the high temperature gas are accommodated in the outer cylinder 104. Has been done. Further, on the outer peripheral portion of the outer cylinder 104 in the large-diameter cylindrical body 106 and the closed cylindrical body 108, a second coolant 120 that also cools the gas and a filter 122 for preventing inflow of debris into the bag body are provided. It is housed.

In the inflator 100 having the above-described structure, the seam (W2) between the outer peripheral surface of the passenger side end of the inner cylinder 102 and the inner peripheral surface of the passenger side end of the outer cylinder 104 is laser beam welded (in this case, After flare joint welding), the occupant side end surface of the large-diameter cylindrical body 106 and the occupant side end surface of the outer cylinder 104 are laser beam welded by a lap joint. In addition, this welding site is illustrated as (W1).

Further, projecting portions 108A and 108B are concentrically formed by press molding on the end surface of the closed cylindrical body 108 on the side opposite to the occupant. Of these, a joint (W3) between the inner protrusion 108A and the outer peripheral surface of the inner cylinder 102 on the side opposite to the occupant, and the outer protrusion 108B and the outer peripheral surface of the outer cylinder 104 on the side opposite to the occupant. The seams (W4) are laser beam welded. Laser beam welding (in this case, also flare joint welding) is performed at the joint (W5) between the outer peripheral surface of the closed cylinder 108 on the passenger side and the root of the flange 106A of the large diameter cylinder 106. It has become so. In this manner, the inflators 100 are integrally formed by laser beam welding the members to each other at the welded portions W1 to W5.

[0007]

[Problems to be solved by the device]

 However, in the case of the inflator 100 described above, the welding in (W1), (W3), and (W4) is not flare joint welding, so the welding area is reduced, and there is a risk that the joint strength at these portions will be insufficient. is there.

Regarding the welded portions (W1), (W3), and (W4) which are not flare joint welding, it is necessary to confirm the welding condition after the welding work is completed, but the welding is performed from the outside of the inflator 100. Since the surface is invisible, it is difficult to judge the quality of the welding situation, and the reliability of welding is reduced.

In view of the above facts, an object of the present invention is to provide an inflator for an airbag device, which can secure sufficient bonding strength and can improve reliability for welding.

[0010]

[Means for Solving the Problems]

 INDUSTRIAL APPLICABILITY The present invention is an inflator used in an airbag device for inflating a bag toward an occupant when the vehicle suddenly decelerates, and ejects gas into the bag during sudden vehicle deceleration. A bottomed cylindrical inner cylinder for accommodating a sensor that senses and an ignition agent that ignites when the sensor operates, and the ignition agent that is arranged in contact with the outer peripheral surface of the inner cylinder. An annular bottomed intermediate cylinder that stores a gas generating agent that generates gas when ignited, and a bottomed annular cylinder that is placed in contact with the outer peripheral surface of the intermediate cylinder and guides the gas into the bag body. And an outer peripheral surface of both axial ends of the inner cylinder, inner peripheral surfaces of both axial ends of the intermediate cylinder, and outer peripheral surfaces of both axial end portions of the intermediate cylinder. Set the inner peripheral surfaces of both ends of the outer cylinder in the axial direction to It is characterized in that it has joined the A joint weld.

[0011]

[Action]

 According to the above configuration, the outer peripheral surfaces of both axial ends of the inner cylinder of the inflator, the inner peripheral surfaces of both axial end portions of the intermediate cylinder, and the outer peripheral surfaces of both axial end portions of the intermediate cylinder and both axial end portions of the outer cylinder. The inner peripheral surface of the portion is joined by flare joint welding, which forms the outer shell of the inflator. Therefore, the inner cylinder, the intermediate cylinder, and the outer cylinder, which form the outer shell of the inflator, are connected to each other by the flare joint welding, so that a sufficient welding area is secured. Therefore, a predetermined bonding strength can be obtained.

In addition, since a sufficient welding area is secured in the above-mentioned flared joint welding portion, it is possible to secure the reliability of welding without visually confirming the welding condition of the welding portion after welding work. can do. Therefore, as compared with the conventional structure, the reliability of welding performed when the inflator is constructed can be improved.

[0013]

【Example】

 An inflator 10 according to an embodiment of the present invention will be described below with reference to FIGS. 1 and 2.

FIG. 2 shows a schematic configuration of the driver-side airbag device 12 including the inflator 10. The airbag device 12 is attached to the hub 14A of the steering wheel 14. The airbag device 12 includes a base plate 16, and an airbag cover 18 is attached to the occupant side of the base plate 16. The airbag cover 18 is made of resin, and a substantially H-shaped thin portion 20 is formed on the occupant side surface. The airbag cover 18 is broken and deployed at the thin portion 20 when the vehicle decelerates rapidly. A bag body 22 is arranged between the airbag cover 18 and the base plate 16 in a folded state. A circular opening is formed in the center of the bag body 22 on the side opposite to the occupant, and a ring plate 24 is arranged on the inner peripheral edge of the opening. Correspondingly, a circular through hole is formed in the central portion of the base plate 16, and the passenger-side half of the substantially cylindrical inflator 10 is inserted into this through hole. A flange 26 is integrally formed at an axially intermediate portion of the inflator 10, and the flange 26 and the ring plate 24 are fastened together on the base plate 16. As a result, the peripheral edge of the opening of the bag body 22 is fixed while being pressed against the base plate 16 side. Further, gas holes 28 are formed at predetermined intervals on the occupant side peripheral surface of the inflator 10, and gas is allowed to flow into the bag body 22 from the gas holes 28 when the vehicle is suddenly decelerated.

Next, the inflator 10 described above will be described in detail with reference to FIG. As shown in this figure, a hollow cylindrical inner cylinder body 30 is arranged at the axial core of the inflator 10. The inner cylinder body 30 includes an inner cylinder body bottom wall 30A located at an end on the occupant side, and an inner cylinder body peripheral wall 30B extending from the peripheral edge of the inner cylinder body bottom wall 30A toward the occupant side. , Consists of. An end of the inner cylinder body 30 on the side opposite to the occupant is opened, and a dish-shaped inner cylinder lid 32 is fitted into this opening. More specifically, the inner cylinder lid peripheral wall 32A of the inner cylinder lid 32 and the inner cylinder main body peripheral wall 30B (the end portion on the occupant side) are fitted so as to be in close contact with each other. Thereby, the inner cylinder body 30 and the inner cylinder lid 32 form a hollow cylindrical inner cylinder. A flare portion is formed by the inner cylinder lid peripheral wall 32A and the inner cylinder main body peripheral wall 30B (end portion on the occupant side).

A dish-shaped enhancer case 34 is housed in the inner cylinder body 30 at a position separated from the inner cylinder body bottom wall 30A by a predetermined distance. The enhancer case 34 includes a bottom portion 34A and a peripheral wall portion 34B extending from the peripheral edge of the bottom portion 34A toward the occupant. A pair of positioning projections 36 are formed on the side surface of the occupant of the bottom portion 34A of the enhancer case 34 at positions facing each other in the radial direction. Further, a pair of detonators (ignition agents) 38 are attached to the side surfaces of the occupant of the bottom portion 34A at positions facing each other in the radial direction. The positioning protrusions 36 and the detonators 38 are arranged alternately at 90 ° intervals in the same plane. The peripheral wall portion 34B of the enhancer case 34 and the inner cylinder main body peripheral wall 30B are formed with coaxial communication holes 40 and 42, respectively, which penetrate through them in the thickness direction.

On the other hand, a disk-shaped enhancer (transfer agent) 44 is accommodated on the passenger side of the detonator 38. The detonator 38 and the enhancer 44 described above correspond to the ignition agent in the present invention. The enhancer 44 is partially inserted in a dish-shaped enhancer lid 46. In the state where the enhancer 44 is arranged, the peripheral surface of the enhancer 44 and the communication holes 40 and 42 face each other, and the heat generated in the enhancer 44 at the time of sudden deceleration of the vehicle is transmitted to the gas generating agent 60 described later. It is like this. A cushion material 48 is interposed between the enhancer lid 46 and the inner cylinder bottom wall 30A.

A sensor 52 having a substantially columnar shape is housed in the inner cylinder body 30 via an O-ring 50 between the inner cylinder body 30 and the enhancer case 34. The sensor 52 is of a mechanical ignition type, and is configured such that when a vehicle is suddenly decelerated, a ball (not shown) inertially moves to cause an ignition pin to move by an urging force to strike the detonator 38. A cushion member 54 is interposed between the sensor 52 and the inner cylinder lid 32.

An intermediate cylinder body 56 is arranged on the outer peripheral portion of the inner cylinder body 30 described above. The intermediate cylinder body 56 includes an intermediate cylinder body bottom wall 56A located on the occupant side, an intermediate cylinder body inner peripheral wall 56B extending from the inner and outer peripheral edges of the intermediate cylinder body bottom wall 56A toward the occupant side, respectively. The intermediate cylinder body outer peripheral wall 56C. The intermediate cylinder body inner peripheral wall 56B is formed shorter than the intermediate cylinder body outer peripheral wall 56C. A dish-shaped intermediate cylinder cover 58 is fitted into the opening of the intermediate cylinder body 56 at the end on the side opposite to the occupant. More specifically, the intermediate cylinder lid inner peripheral wall 58A and the inner cylinder main body peripheral wall 30B of the intermediate cylinder lid 58, and the intermediate cylinder lid outer peripheral wall 58B and the intermediate cylinder main body outer peripheral wall 56C of the intermediate cylinder lid 58 are tightly packed, respectively. Are fitted so as to abut. As a result, the intermediate cylinder body 56 and the intermediate cylinder cover 58 form a hollow annular intermediate cylinder. The intermediate cylinder body inner peripheral wall 56B (the occupant side end) and the inner cylinder body peripheral wall 30B (the occupant side end), and the intermediate cylinder lid inner peripheral wall 58A and the inner cylinder body peripheral wall 30B (the vicinity of the anti-occupant side end). Further, flare portions are formed by the outer peripheral wall 58B of the intermediate cylinder lid body and the outer peripheral wall 56C of the intermediate cylinder main body (end portion on the occupant side).

The gas generating agent 60 is enclosed in most of the occupant side between the intermediate cylinder body 56 and the intermediate cylinder lid 58. Further, a portion of the intermediate cylinder main body 56 and the intermediate cylinder lid 58 on the side opposite to the occupant (a portion of the intermediate cylinder lid 58 on the occupant side) is covered with the cushioning material 64 with the first coolant 62. It is arranged. A communication hole 66 is formed at a position adjacent to the first coolant 62 (on the occupant side of the outer peripheral wall 56C of the intermediate cylinder body). As a result, the gas that has passed through the first coolant 62 is guided into the lower outer cylinder 70 described later.

On the outer peripheral portion of the intermediate cylinder body 56, an upper outer cylinder 68 is arranged on the occupant side thereof. The upper outer cylinder 68 includes an upper outer cylinder bottom wall 68A located on the passenger side, and an upper outer cylinder inner peripheral wall 68B extending from the inner and outer peripheral edges of the upper outer cylinder bottom wall 68A toward the occupant side. And an outer peripheral wall 68C of the upper outer cylinder. The upper outer cylinder inner peripheral wall 68B is shorter than the upper outer cylinder outer peripheral wall 68C. An end of the upper outer cylinder outer peripheral wall 68C on the side opposite to the occupant is bent and extended in the radial direction of the inflator 10 and serves as the flange 26 described above. Further, the gas hole 28 described above is also formed in the middle portion of the outer peripheral wall 68C of the upper outer cylinder.

A lower outer cylinder 70 is arranged on the side opposite to the occupant of the upper outer cylinder 68. The lower outer cylinder 70 has a lower outer cylinder occupant side bottom wall 70A whose end on the occupant side is bent toward the axial center of the inflator 10, and an outer peripheral edge of the lower outer cylinder occupant side bottom wall 70A, which faces the occupant side. And the lower outer cylinder outer peripheral wall 70B extending obliquely, and the lower outer cylinder occupant side bottom wall 70A from the end of the lower outer cylinder outer peripheral wall 70B opposite to the passenger side toward the axial center of the inflator 10. A lower outer cylinder anti-occupant side bottom wall 70C extending in parallel, and a lower outer cylinder inner peripheral wall 70D bent from the axial center side end of the lower outer cylinder anti-occupant side bottom wall 70C toward the passenger side. , Consists of. The lower outer cylinder 70 is fitted into the upper outer cylinder 68. More specifically, the lower outer cylinder inner peripheral wall 70D and the intermediate cylinder body outer peripheral wall 56C are fitted so that the lower outer cylinder outer peripheral wall 70B and the upper outer cylinder outer peripheral wall 68C are in close contact with each other. In the fitted state, the lower outer cylinder 70 and the upper outer cylinder 68 are communicated with each other through the communication hole 71. The upper outer cylinder inner peripheral wall 68B and the intermediate cylinder main body outer peripheral wall 56C (passenger side end), and the upper outer cylinder outer peripheral wall 68C and lower outer cylinder outer peripheral wall 70B (near the occupant side end) further lower. The outer cylinder inner peripheral wall 70D and the intermediate cylinder main body outer peripheral wall 56C form flare portions, respectively.

A second coolant 74 is arranged in the lower outer cylinder 70 via a retainer 72, and a filter 76 is arranged in the upper outer cylinder 68. Therefore, the gas generated by the combustion of the gas generating agent 60 is cooled by the first coolant 62 and the second coolant 74, and after the debris after the combustion of the gas generating agent 60 is removed by the filter 76. The gas is introduced into the bag body 22 through the gas holes 28.

The operation of this embodiment will be described below through an assembling procedure for forming the inflator 10.

First, the inner cylinder body 30, the intermediate cylinder body 56, and the upper outer cylinder 68 are assembled with each other. That is, the inner cylinder body peripheral wall 30B (passenger side end portion) and the intermediate cylinder body inner peripheral wall 56B (passenger side end portion) are laser beam welded at the flare portion (P1). At the same time, the intermediate cylinder body outer peripheral wall 56C (passenger side end) and the upper outer cylinder inner peripheral wall 68B (passenger side end) are laser beam welded at the flare portion (P2). The flare portion (P2) may be laser beam welded first, and then the flare portion (P1) may be laser beam welded.

Next, the filter 76 is inserted and arranged in the upper outer cylinder 68. Then, the lower outer cylinder 70 is fitted into the upper outer cylinder 68. At this time, the second coolant 74 is set in advance in the lower outer cylinder 70 by the retainer 72.

Next, after the gas generating agent 60 is sealed in the intermediate cylinder body 56, the first coolant 62 is arranged via the plurality of cushioning materials 64. Then, the intermediate cylinder cover 58 is fitted.

Next, after the cushion member 48 is inserted and arranged in the inner cylinder body 30, the enhancer lid 46, the enhancer 44, the detonator 38, and the enhancer case 34 are integrally inserted and arranged. Then, after the O-ring 50 is attached, the sensor 52 is inserted and arranged while the positioning protrusion 36 positions the sensor 52. After the assembly of the sensor 52 is completed, the cushion material 54 is inserted and arranged, and then the inner cylinder lid body 32 is fitted.

All of the above-described assembly of parts is performed with the direction of arrow A in FIG. 1 as the assembly direction.

Next, after the assembling of these parts is completed, first, the inner cylinder body peripheral wall 30B (end portion on the occupant side) and the intermediate cylinder lid inner peripheral wall 58A form the flare portion (P4) and the intermediate cylinder. The outer peripheral wall 58B of the lid body and the outer peripheral wall 56C of the intermediate cylinder main body (end portion on the occupant side) are flares (P5), and the outer peripheral wall 56C of the intermediate cylinder main body (end portion on the occupant side) and the lower outer cylinder inner peripheral wall 70D. Are laser beam welded at the flare portion (P6), and the upper outer cylinder outer peripheral wall 68C and the lower outer cylinder outer peripheral wall 70B are laser beam welded at the flare portion (P7). Then, finally, the inner cylinder lid peripheral wall 32A and the inner cylinder main body peripheral wall 30B (end portion on the occupant side) are laser beam welded at the flare portion (P3). The welding procedure from the flare portion (P4) to the flare portion (P7) is not limited to the above procedure, and may start from any one. As a result, all welding work is completed, and the inflator 10 is constructed.

The inflator 10 is assembled in the airbag device 12 and then assembled in the hub 14 A of the steering wheel 14. When the vehicle suddenly decelerates, the sensor 52 senses this and ignites the detonator 38, and the gas generating agent 60 burns via the enhancer 44. As a result, a large amount of gas is generated, cooled by the first coolant 62 and the second coolant 74, and then flows into the bag 22 through the gas holes 28 through the filter 76. Therefore, the bag body 22 expands to break the airbag cover 18 at the thin portion 20. As a result, the bag body 22 bulges toward the occupant side.

As described above, in this embodiment, the inflator 10 of the airbag device 12 includes the inner cylinder including the inner cylinder body 30 and the inner cylinder lid 32, and the intermediate cylinder body 56 and the intermediate cylinder lid 58. It is composed of an intermediate cylinder and an outer cylinder composed of an upper outer cylinder 68 and a lower outer cylinder 70, and flare joint welding is performed at the flare portions (P1) to (P7) (the welding method itself is a laser beam). Since the inner cylinder, the intermediate cylinder, and the outer cylinder are assembled with each other by welding, a sufficient welding area can be secured. Therefore, it is possible to improve the joint strength between the inner cylinder, the intermediate cylinder, and the outer cylinder that form the inflator 10.

Further, since all the flare joint welding is performed to ensure a sufficient welding area as described above, it is not necessary to visually check the welding condition after the welding work is completed, and the reliability of the welding is improved. Can be secured. Therefore, as compared with the conventional structure, it is possible to improve the reliability of welding when the inflator 10 is configured.

In this embodiment, P1 to P7 are all used as flare joints for flare joint welding, but the present invention is not limited to this, and the outer peripheral surfaces of the axially opposite end portions of the inner cylinder and the axially opposite end portions of the intermediate cylinder are also joined. Flare joint welding may be performed on the inner peripheral surface and the outer peripheral surfaces of both axial ends of the intermediate cylinder and the inner peripheral surfaces of both axial end portions of the outer cylinder. The flare parts (P3), (P5), (P7) ), A joint structure other than flare joint welding may be used. For example, the flare parts (P3) and (P5) are connected by caulking or screwing, and the flare part (P7) is also formed by projecting a flange on the lower outer cylinder outer peripheral wall 70B to form a connection structure with screws or the like. May be used.

Further, the welding method is not limited to laser beam welding, and the same effect can be obtained by electron beam welding or the like.

[0036]

[Effect of device]

 As described above, the inflator for an airbag device according to the present invention has an excellent effect that it is possible to secure sufficient joint strength and to improve reliability for welding.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of an inflator to which the present invention is applied, taken along a plane including an axis.

FIG. 2 is a schematic configuration diagram showing an airbag device including the inflator of FIG.

FIG. 3 is a sectional view corresponding to FIG. 1 according to the prior art of the present invention.

[Explanation of symbols]

 10 Inflator 12 Airbag Device 22 Bag Body 28 Gas Hole 30 Inner Cylinder Body (Inner Cylinder) 32 Inner Cylinder Lid (Inner Cylinder) 38 Detonator (Ignition Agent) 44 Enhancer (Ignition Agent) 52 Sensor 56 Intermediate Cylinder Body (Middle Cylinder) ) 58 intermediate cylinder lid (intermediate cylinder) 60 gas generating agent 68 upper outer cylinder (outer cylinder) 70 lower outer cylinder (outer cylinder) P1 flare part P2 flare part P4 flare part P6 flare part

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoshihide Sakaguchi Noda No. 1 Oita-cho, Oguchi-machi, Niwa-gun, Aichi Prefecture Tokai Rika Electric Co., Ltd. (72) Akira Kawaguchi Oita-machi, Niwa-gun, Aichi Prefecture Noda No. 1 Tokai Rika Electric Co., Ltd. (72) Minor Abe Minoru Abe Oguchi Town, Oita Town, Aichi Prefecture No. 1 Noda, Tokai Rika Electric Co., Ltd.

Claims (1)

[Scope of utility model registration request] 1. An inflator used for an airbag device for inflating a bag toward an occupant when the vehicle suddenly decelerates, and ejecting gas into the bag during sudden deceleration of the vehicle. A bottomed cylindrical inner cylinder that houses a sensor that senses the state and an igniting agent that ignites when the sensor operates, and the igniting agent that is arranged in contact with the outer peripheral surface of the inner cylinder. An annular bottomed intermediate cylinder that stores a gas generating agent that generates gas when ignited, and an annular bottomed outer cylinder that is arranged in contact with the outer peripheral surface of the intermediate cylinder and guides the gas into the bag body. A cylinder, and outer peripheral surfaces of both axial ends of the inner cylinder, inner peripheral surfaces of both axial ends of the intermediate cylinder, and outer peripheral surfaces of both axial ends of the intermediate cylinder and the outer cylinder. Replace the inner peripheral surface of both ends in the axial direction with Air bag device for an inflator, characterized in that joined by A joint weld.