JP2019104448A - Gas generator and method of manufacturing gas generator - Google Patents

Abstract

To provide a gas generator that can easily suppress occurrence of defective attachment of a retainer or the like, and a method of manufacturing the gas generator.SOLUTION: A gas generator 1 includes a housing 10, a post-welding fixture, and a junction part 6. The post-welding fixture includes a rod-like part and a post-welding head 11. The post-welding head 11 has a flange part 4 positioned on a rod-like part side, and a post-welding projection 12. The post-welding projection 12 projects from the flange part 4 toward the opposite side of a side on which the rod-like part is positioned. The junction part 6 fills a clearance between a top surface 14b of the post-welding projection 12 and an outer peripheral surface of the housing 10, and is positioned closer to the housing 10 side than an annular surface 4b positioned on the rod-like part side of the flange part 4 in the axial direction of the rod-like part.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a gas generator incorporated in an air bag apparatus as an occupant protection apparatus installed in an automobile etc., and in particular, a so-called cylinder type gas generation having a long columnar shape which is suitably incorporated in a side air bag apparatus etc. Related to

  Conventionally, from the viewpoint of protecting an occupant of a car or the like, an airbag device as an occupant protection device has become widespread. The airbag device is provided for the purpose of protecting the occupant from the impact generated at the time of a collision such as a vehicle, and the airbag serves as a cushion by expanding and expanding the airbag instantaneously at the time of a collision such as a vehicle. It is something to receive the body. The gas generator is incorporated in this air bag device, and in the event of a collision of a vehicle or the like, the igniter is ignited by energization from the control unit, and the gas generating agent is burned by the flame generated in the igniter to generate a large amount of gas instantly This is a device that inflates and deploys the airbag.

  There are various types of gas generators based on specifications such as the installation position and output for a vehicle or the like. One of them is a so-called cylinder type gas generator. The external shape of the cylinder type gas generator is a long columnar shape, and is suitably incorporated into a side airbag device, a curtain airbag device, a knee airbag device, a seat cushion airbag device, and the like.

  On the outer peripheral surface of the cylinder type gas generator, a stud bolt for attaching to a retainer or the like of an air bag device may be provided. Japanese Patent No. 3958304 (Patent Document 1) discloses a technique for welding and attaching a stud bolt to the outer peripheral surface of a gas generator having a planarized surface. Further, Japanese Patent Application Laid-Open No. 2005-313752 (Patent Document 2) discloses a technique for welding and attaching the head of a headed bolt having a curved surface to a curved outer peripheral surface of a gas generator. .

Patent No. 3958304 JP 2005-313752 A

  However, in the configurations as disclosed in Patent Document 1 and Patent Document 2, although the gas generator and the bolt can be firmly joined, the outer peripheral surface of the gas generator or the head of a headed bolt can be used. Special shape processing is required, which complicates the manufacturing process and increases the manufacturing cost. When the welding process is carried out without adopting any of the configurations of Patent Document 1 and Patent Document 2 above, the welded joint portion protrudes from between the head of the headed bolt and the outer peripheral surface of the gas generator. Not only the appearance defect but also the attachment defect of the retainer or the like of the air bag device may occur.

  Therefore, the present invention has been made in view of the above-described point, and an object of the present invention is to provide a gas generator and a method of manufacturing the gas generator that can easily suppress the occurrence of mounting defects such as a retainer.

  The gas generator according to the present invention comprises a housing having a substantially cylindrical outer shape, a post welding attachment, and a joint. The post-welding fixture is attached to the curved outer peripheral surface of the housing. The joint portion joins the housing and the post-welding fixture by melting and then solidifying a part of the pre-welding fixture. The post-welding fixture includes a rod-like portion and a welding rear head. The welding rear portion is provided at one end of the rod-like portion and faces the outer peripheral surface of the housing via the joint portion. The welding rear portion has a flange portion located on the rod-like portion side and a projection after welding. The post-welding projection projects from the flange toward the opposite side to the side where the rod-like portion is located. The joint portion fills the space between the top surface of the projection after welding and the outer peripheral surface of the housing, and an annular portion located on the rod portion side of the flange portion in the axial direction of the rod portion. It is located in the said housing side rather than the surface.

  In the gas generator according to the present invention, the joint portion is preferably positioned closer to the housing than the flange portion in the axial direction of the rod portion.

  In the gas generator according to the present invention, the flange portion is formed by providing the post-welding annular step portion defined by the flange portion and the post-welding projection portion on the periphery of the welding rear head. It may have a facing surface which defines a part of the rear annular step portion and faces the outer peripheral surface of the housing, in which case the joining portion is joined to at least a portion of the facing surface. Is preferred.

  In the gas generator according to the present invention, in the direction parallel to the radial direction of the rod-like portion, the outer end of the joint portion is inside the outer end of the flange portion and protrudes after the welding It is preferable to reach a position outside the top surface of the part.

  In the gas generator according to the present invention, the outer diameter of the flange portion is preferably 1.2 or more times the outer diameter of the root portion of the projecting portion after welding.

  The method of manufacturing a gas generator according to the present invention comprises the steps of: applying a voltage to a housing and a welding pre-welding member arranged to face each other at a distance, and applying a voltage to the housing and the welding pre-welding fitting. Bringing the housing and the pre-welding fixture close while maintaining, thereby welding the housing and the pre-welding fixture by welding. The housing has a substantially cylindrical outer shape. The pre-welding fixture includes a rod-like portion and a welding forehead. The welding front portion is provided at one end of the rod-shaped portion. The welding front portion has a flange portion and a projection before welding. The said flange part is located in the said rod-shaped part side. The projection before welding protrudes from the flange toward the opposite side to the side where the rod-like portion is located. The step of joining the housing and the welding attachment by welding locally heats the projection before welding by generating an electric discharge between the welding front head and the housing, and the heating causes the welding to proceed. A part of the projection before welding is melted and then solidified to form a joint that joins the housing and the attachment after welding. In the step of welding the housing and the pre-welding fixture, the joint fills the space between the top surface of the unwelded portion of the pre-welding projection and the curved outer peripheral surface of the housing. At the same time, the housing and the attachment before welding are joined under the condition that the housing is located on the side of the housing relative to the annular surface located on the side of the rod portion of the flange portion in the axial direction of the rod portion.

  In the method of manufacturing a gas generator according to the present invention, in the step of joining the housing and the attachment before welding by welding, the joint portion is closer to the rod portion than the flange portion in the axial direction. Preferably, the housing and the attachment before welding are joined under the condition of being located on the housing side.

  In the method of manufacturing a gas generator according to the present invention, the welding front portion may have an annular step before welding defined by the flange portion and the projection before welding at the periphery thereof. In that case, in the step of joining the housing and the attachment before welding by welding, the flange defines a part of the annular step before welding and faces the outer peripheral surface of the housing. It is preferable that joining of the housing and the attachment before welding be performed under the condition of joining to at least a part of the facing surface of the part.

  In the method of manufacturing a gas generator according to the present invention, the outer end of the joint portion is inside the outer end of the flange portion in the direction parallel to the radial direction of the rod-like portion, and It is preferable that the housing and the attachment before welding be joined under the condition that the position before the top surface of the non-melted portion of the projection before welding reaches a position outside the top surface.

  In the manufacturing method of the gas generator based on the said invention, it is preferable that the outer diameter of the said flange part is 1.2 times or more of the outer diameter of the root part of the said projection part before welding.

  ADVANTAGE OF THE INVENTION According to this invention, it can be set as the manufacturing method of the gas generator which can suppress generation | occurrence | production of attachment defects, such as a retainer, easily, and a gas generator.

It is the schematic of the cylinder type gas generator in embodiment. It is a perspective view of the welding front attachment in an embodiment. It is sectional drawing in alignment with the III-III line of the stud bolt before welding shown in FIG. It is the schematic of a pre-welding stud bolt and a housing. It is a schematic sectional drawing of a stud bolt and a housing after welding. It is a flowchart which shows a part of process of the manufacturing method of the gas generator according to embodiment.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The embodiment shown below illustrates the case where the present invention is applied to a cylinder type gas generator incorporated in a side airbag device. In the embodiments described below, the same or common parts are denoted by the same reference numerals in the drawings, and the description thereof will not be repeated.

<Gas generator 1>
FIG. 1 is a schematic view of a cylinder type gas generator 1 in the embodiment. The cylinder type gas generator 1 in the present embodiment has a substantially cylindrical outer shape. The gas generator 1 comprises a housing 10. The arrow DR1 illustrated in FIG. 1 indicates the axial direction DR1 of the gas generator 1. The axial direction DR1 is the left-right direction in FIG.

  One end and the other end of the housing 10 in the axial direction DR1 are closed. The housing 10 has a substantially cylindrical outer shape. The outer peripheral surface of the housing 10 is curved. The housing 10 includes a housing body 90, a holder 20 and a closure member 30.

  Inside the housing 10 constituted by the housing body 90, the holder 20 and the closing member 30, an igniter 40 as an internal component, a partition member 50, a storage chamber defining member 60, a gas generating agent 70, a filter 80, etc. Is housed. Inside the housing 10, a combustion chamber S1 in which the gas generating agent 70 of the above-mentioned internal components is mainly disposed, and a filter chamber S2 in which the filter 80 is disposed are located.

  The housing body 90 constitutes a peripheral wall portion of the housing 10. The housing body 90 is an elongated cylindrical member having openings formed at both ends in the axial direction DR1. The housing main body 90 is made of, for example, a high tensile steel pipe member (STK, STKM, etc.). The outer diameter of the housing body 90 is preferably 15 mm or more and 40 mm or less.

  The holder 20 is fixed to the housing body 90 so as to close one end of the housing 10 in the axial direction DR1. The closing member 30 is fixed to the housing body 90 so as to close the other end of the housing 10 in the axial direction DR1.

  The igniter 40 is attached to the one end described above by being supported by the holder 20. The igniter 40 is for burning the gas generating agent 70 and is installed to face the space inside the housing 10.

  At a predetermined position of the space inside the housing 10, a partition wall member 50 as a partition portion is disposed. The partition member 50 is a member for dividing the space inside the housing 10 into the combustion chamber S1 and the filter chamber S2 in the axial direction DR1.

  A storage chamber defining member 60 and a gas generating agent 70 are disposed in a space (i.e., a combustion chamber S1) which is sandwiched by the holder 20 and the partition member 50 in the space inside the housing 10.

  The storage chamber defining member 60 is a member defining the gas generating agent storage chamber S1A in which the gas generating agent 70 is stored, and is a relatively fragile member so that the gas generating agent 70 ruptures or melts as it burns. Is configured.

  The gas generating agent 70 is an agent that generates a gas by igniting and burning by heat particles generated by the igniter 40 operating. As the gas generating agent 70, a non-azide gas generating agent is preferably used, and the gas generating agent 70 is generally configured as a molded body containing a fuel, an oxidant and an additive.

  In the space inside the housing 10, the filter 80 is disposed in the space (i.e., the filter chamber S2) sandwiched by the closing member 30 and the partition member 50. The filter 80 functions as a cooling means for cooling the gas by taking away the high-temperature heat possessed by the gas when the gas generated by the burning of the gas generating agent 70 passes through the filter 80, and in the gas It also functions as a removal means for removing slag (residue) and the like contained in

  A plurality of gas jet outlets 31 are provided along the circumferential direction of the housing main body 90 and the axial direction DR1 in the housing main body 90 of the portion defining the filter chamber S2. The plurality of gas jet outlets 31 are for discharging the gas after passing through the filter 80 to the outside of the housing 10.

  The gas generator 1 further comprises a post-welding fixture. In the embodiment, the post-welding fixture is a post-weld stud bolt 16. A plurality of post-weld stud bolts 16 are welded and attached to the housing 10. After welding, a retainer or the like of the air bag device is attached to the stud bolt 16. After welding, the stud bolt 16 is attached to the curved outer peripheral surface of the housing 10.

  In the embodiment, the number of stud bolts 16 after welding attached to the gas generator 1 is two, but may be one or three or more.

(Attachment before welding)
FIG. 2 is a perspective view of the welding pre-welding fixture in the embodiment. In the embodiment, the pre-welding attachment is the pre-welding stud bolt 2. FIG. 3 is a cross-sectional view of the pre-welding stud bolt 2 shown in FIG. 2 along the line III-III. The pre-welding stud bolt 2 will be described with reference to FIGS. 2 and 3.

  The pre-welding stud bolt 2 includes a rod-like portion and a welding front head 9. In the embodiment, the rod-shaped portion is a rod-shaped bolt portion 3. A male screw portion is formed on the outer peripheral surface of the bolt portion 3.

  Arrows DR2 and DR3 illustrated in the drawing indicate the axial direction DR2 of the bolt portion 3 and the radial direction DR3 of the bolt portion 3. The axial direction DR2 is the vertical direction in FIG. The radial direction DR3 is the left-right direction in FIG. The radial direction DR3 is substantially parallel to the axial direction DR1.

  The welding front portion 9 is provided at one end of the bolt portion 3 in the axial direction DR2. The welding front portion 9 has a flange 4 and a projection 5 before welding. The flange portion 4 is located on the bolt portion 3 side of the welding front portion 9. The flange portion 4 is provided at one end of the bolt portion 3 in the axial direction DR2. The flange portion 4 has a substantially disc shape. The thickness direction of the flange portion 4 is the axial direction DR2.

  The flange portion 4 has an opposing surface 8, an outer end 4 a and an annular surface 4 b. The facing surface 8 faces the outer circumferential surface of the housing 10 at the time of welding. The outer end 4a is an end of the flange 4 in a direction parallel to the radial direction DR3. The annular surface 4 b is located on the bolt portion 3 side of the flange portion 4 in the axial direction DR <b> 2 of the bolt portion 3. The annular surface 4 b is a surface of the surface of the flange portion 4 located on the bolt portion 3 side. The annular surface 4 b is annularly located around the bolt portion 3. A retainer or the like of the air bag device is mounted on the annular surface 4b.

  The projection 5 before welding protrudes from the flange 4 toward the opposite side to the side where the bolt 3 is located. The projection 5 before welding protrudes from the flange 4 in a direction away from the bolt 3.

  The projection 5 before welding has a tapered surface 15a and a top surface 14a. The tapered surface 15 a is continuous with the facing surface 8. The tapered surface 15 a has a tapered shape in which the outer diameter of the projection 5 before welding becomes larger as it approaches the flange 4. The tapered surface 15 a constitutes the outer periphery of the pre-welding protrusion 5.

  The top surface 14 a has a curved shape protruding in a direction away from the bolt portion 3. The top surface 14a is continuous with the tapered surface 15a. The top surface 14a is provided at one end of the pre-welding stud bolt 2 in the axial direction DR2. The top surface 14 a is the surface of the welding front portion 9 that is most distant from the bolt portion 3.

  The welding front portion 9 has an annular step 13 before welding. The pre-welding annular step 13 is defined by the flange 4 and the pre-welding projection 5. The pre-welding annular step 13 is defined at the periphery of the welding front portion 9. The pre-welding annular step portion 13 is defined by the tapered surface 15 a and the opposing surface 8.

  FIG. 4 is a schematic view of the stud bolt 2 before welding and the housing 10. Only the housing 10 is illustrated in cross section in FIG. When welding the stud bolt 2 before welding and the housing 10 by welding, the housing 10 and the stud bolt 2 before welding are brought close to each other, and the projection 5 before welding is pressed against the curved outer peripheral surface of the housing 10 (FIG. 4) White hollow arrow A). At this time, a part of the projection 5 before welding is melted (region R in FIG. 4), and a joint 6 to be described later is formed. Thereby, the housing 10 and the stud bolt 2 before welding are joined.

  As a method of attaching the gas generator 1 to a retainer or the like of an air bag apparatus, for example, a method of welding the necessary portions while press-fitting the rod portion of the fixture into the through hole formed in the retainer, the rod portion in the through hole of the retainer There is a method of welding to insert the required portion while crushing and fixing the end portion of the rod portion, and a method of welding the retainer and the rod portion (laser welding, friction welding, etc.). Also in the method, it is preferable that the molten metal produced by the joining of the outer peripheral surface of the housing 10 and the fixture does not rise on the annular surface 4 b of the flange portion 4. The above-mentioned rod-like portion may have a configuration in which a male screw portion is not formed.

  FIG. 5 is a schematic cross-sectional view of the stud bolt 16 and the housing 10 after welding. The gas generator 1 further comprises a junction 6. The joint 6 joins the housing 10 and the post-welding stud bolt 16 by welding by melting and solidifying a part of the pre-welding stud bolt 2 (the pre-welding protrusion 5).

  The post-welding stud bolt 16 includes a bolt portion 3 and a welding rear portion 11. The welding back portion 11 is formed by melting the welding front portion 9. The welding back portion 11 is provided at one end of the bolt portion 3 in the axial direction DR2. The welding back portion 11 is opposed to the outer peripheral surface of the housing 10 via the joint portion 6.

  The welding back portion 11 has a flange portion 4 and a post-welding projecting portion 12. The post-welding projection 12 is formed by melting the welding front portion 9. The post-welding protrusion 12 protrudes from the flange 4 toward the opposite side to the side where the bolt 3 is located. The post-welding projection 12 has a tapered surface 15 b and a top surface 14 b. The tapered surface 15 b is continuous with the facing surface 8. The tapered surface 15 b has a tapered shape in which the outer diameter of the projecting portion 12 after welding increases as the flange portion 4 is approached. The tapered surface 15 b constitutes the outer periphery of the projection 12 after welding.

  The top surface 14 b has a curved shape that is recessed toward the bolt portion 3. The top surface 14b is continuous with the tapered surface 15b. The top surface 14b is provided at one end of the post-weld stud bolt 16 in the axial direction DR2. The top surface 14 b is the surface of the welding rear portion 11 that is the most remote from the bolt portion 3. The top surface 14b (top surface 14a) may have a shape other than a curved shape, and fine irregularities on the top surface 14b (top surface 14a) are ignored and treated as a surface.

  An annular step portion 7 after welding is provided at the periphery of the welding rear portion 11. The post-welding annular step 7 is defined by the flange 4 and the post-welding projection 12. By providing the annular step portion 7 after welding, the opposing surface 8 is provided on the flange portion 4. The facing surface 8 faces the outer circumferential surface of the housing 10. The opposing surface 8 defines a part of the annular step portion 7 after welding. The post-welding annular step portion 7 is defined by the tapered surface 15 b and the opposing surface 8.

  The joint portion 6 fills the space between the top surface 14 b and the outer peripheral surface of the housing 10. The joint 6 is positioned closer to the housing 10 than the annular surface 4 b in the axial direction DR2. The joint 6 is located closer to the housing 10 than the flange 4 in the axial direction DR2. The joint 6 has an outer end 6a. The outer end 6a is an end of the joint 6 in the direction parallel to the radial direction DR3. The outer end 6a reaches a position inside the radial direction DR3 from the outer end 4a of the flange portion 4 and a position outside the radial direction DR3 from the top surface 14b of the projection 12 after welding.

  By filling the space between the top surface 14 b and the outer peripheral surface of the housing 10, the joint portion 6 can ensure the bonding strength between the stud bolt 16 and the housing 10 after welding. Further, since the joint 6 is positioned closer to the housing 10 than the annular surface 4b in the axial direction DR2, the joint surface of the stud bolt 2 before welding or the housing 10 is joined without special shape processing. It can suppress that the part 6 protrudes to the outer side of radial direction DR3 rather than the outer end 4a, and is bulged to the annular surface 4b of the flange part 4. FIG. Thereby, after securing the joint strength, it is possible to easily suppress the occurrence of the defective attachment to the stud bolt 16 after welding such as the retainer of the air bag device.

  Furthermore, since the joint portion 6 is positioned closer to the housing 10 than the flange portion 4 in the axial direction DR2, the attachment defect to the post-welding stud bolt 16 such as a retainer of the air bag device can be more reliably suppressed. be able to.

  By providing the step, the space formed between the facing surface 8 and the tapered surface 15b and the outer peripheral surface of the housing 10 becomes a liquid pool into which the molten metal flows, and the molten metal further flows from the space to the outside of the radial direction DR3. It can be efficiently suppressed from flowing out.

  That is, as described above, the joint 6 remains outside the radial end DR3 with respect to the outer end 4a of the flange 4 because the joint 6 remains inside the radial direction DR3 with respect to the outer end 4a. It is possible to suppress the appearance defects of the gas generator 1 caused by the above.

  Further, the joint 6 is provided between the top surface 14 b and the outer peripheral surface of the housing 10 and outside the radial direction DR 3 more than the top surface 14 b, so that the joint 6 is provided with the top surface 14 b and the housing Compared with the case where it is provided only between 10 and the outer peripheral surface, the joint strength between the stud bolt 16 after welding and the outer peripheral surface of the housing 10 can be improved.

  The bonding portion 6 is preferably bonded to at least a part of the facing surface 8. Thereby, the joint area of the outer peripheral surface of the housing 10 and the welding back part 11 increases. Therefore, the joint strength between the stud bolt 16 and the housing 10 after welding can be improved.

  The outer diameter a of the flange portion 4 is preferably 1.2 or more times the outer diameter b of the root portion of the projecting portion 12 after welding, and 1.6 times the outer diameter b of the root portion of the projecting portion 12 after welding It is more preferable that it is more than. The root portion of the projection 12 after welding is a boundary between the tapered surface 15 b and the opposing surface 8. The outer diameter a of the flange 4 is 12 [mm], for example. The outer diameter b of the root portion of the projection 12 after welding is, for example, 7 mm. By setting the outer diameter a of the flange portion 4 to be 1.2 times or more the outer diameter b of the root portion of the projecting portion 12 after welding, it is possible to secure a region where the opposing surface 8 in the radial direction DR3 is provided. . Thus, the joint 6 can be further suppressed from protruding from the outer end 4 a to the outer side of the radial direction DR 3 and rising on the annular surface 4 b of the flange 4. Therefore, the attachment defect to the stud bolt 16 after welding, such as a retainer of an airbag apparatus, can be suppressed more.

(Joining of stud bolt 2 before welding and outer peripheral surface of housing 10)
FIG. 6 is a flowchart showing a part of the process of the method of manufacturing the gas generator 1 in the embodiment. A part of processes of a method of manufacturing the gas generator 1 will be described with reference to FIGS. 4 to 6.

  In the method of manufacturing the gas generator 1 according to the embodiment, first, in step (S10), a voltage is applied to the housing 10 and the pre-welding stud bolt 2 disposed to face each other with a distance.

  Next, in step (S20), the housing 10 and the pre-welding stud bolt 2 are brought close to each other while maintaining a state in which a voltage is applied to the housing 10 and the pre-welding stud bolt 2. By generating an electric discharge between the welding front portion 9 and the curved outer peripheral surface of the housing 10, the projection 5 before welding is locally heated, and this heating causes a part of the projection 5 before welding (FIG. 4). Melt the region R) of Hereinafter, a part of the molten pre-welding protrusion 5 is referred to as a fused part.

  The fusion zone is held between the welding rear portion 11 and the outer peripheral surface of the housing 10 by being pressed against the outer peripheral surface of the housing 10. As shown in FIG. 5, when the fusion zone is further pushed as it is, it is crushed by the welding rear head 11 and the outer peripheral surface of the housing 10. The melting portion extends along the curved shape of the outer peripheral surface of the housing 10. The melted portion of the crushed portion spreads outside the radial direction DR3 than the top surface 14b. Thereafter, the melted portion is solidified to form the bonding portion 6. Thereby, the housing 10 and the pre-welding stud bolt 2 can be joined by welding.

  In the step (S20), the joint 6 fills the space between the top surface 14b of the unwelded portion (the post-welding protrusion 12) of the pre-welding protrusion 5 and the curved outer peripheral surface of the housing 10 The housing 10 and the pre-welding stud bolt 2 are joined on the condition that the housing 10 is located closer to the housing 10 than the annular surface 4b in the axial direction DR2.

  By the liquid pool formed by the above-described bonding, it is possible to efficiently suppress the flow of the molten metal from the liquid pool to the outside of the radial direction DR3.

  The housing 10 and the pre-welding stud bolt 2 are joined under the condition that the space between the top surface 14b and the curved outer peripheral surface of the housing 10 is filled and the housing 10 is located closer to the housing 10 than the annular surface 4b in the axial direction DR2. As a result, after securing the joint strength between the stud bolt 16 and the housing 10 after welding, it is possible to suppress a mounting defect to the stud bolt 16 after welding, such as a retainer of the airbag device.

  Preferably, the housing 10 and the pre-welding stud bolt 2 are joined under the condition that the joint 6 is positioned closer to the housing 10 than the flange 4 in the axial direction DR2. As a result, it is possible to further suppress defective attachment to the stud bolt 16 after welding such as a retainer of the air bag device.

  Furthermore, under the condition that the outer end 6a of the joint 6 reaches a position inside the radial direction DR3 with respect to the outer end 4a of the flange portion 4 and outside the radial direction DR3 with respect to the top surface 14b, More preferably, welding of the stud bolt 2 before welding is performed. Thereby, the appearance defect of the gas generator 1 can be suppressed.

  In the step (S20) of welding the housing 10 and the pre-welding stud bolt 2 by welding, the housing 10 and the pre-welding stud bolt 2 are joined under the condition that the joint 6 is joined to at least a part of the opposing surface 8 Is preferred. Thereby, the joint strength of the stud bolt 16 and the housing 10 after welding can be improved.

  As shown in FIG. 3, the outer diameter a of the flange portion 4 is preferably 1.2 times or more the outer diameter b of the root portion of the projection 5 before welding, and the outside of the root portion of the projection 5 before welding The diameter b is more preferably 1.6 times or more. The root portion of the projection 5 before welding is a boundary between the tapered surface 15 a and the facing surface 8. As a result, it is possible to further suppress defective attachment to the stud bolt 16 after welding such as a retainer of the air bag device.

  Through the steps (S10) to (S20) shown in FIG. 6, the gas generator 1 shown in FIG. 1 is manufactured.

  The shape connecting the opposing surface 8 and the top surface 14b (the top surface 14a) defining a part of the annular step 7 after welding (the annular step 13 before welding) is a shape other than a taper (for example, a curved shape) It may be.

  In the embodiment, the facing surface 8 is provided by providing the post-welding annular step portion 7 (the pre-welding annular step portion 13), but the facing surface 8 is not provided, and the top face is provided. An annular tapered surface may be provided to connect the end 14 a (the top surface 14 b) and the outer end 4 a of the flange 4. Also in this configuration, an effect according to the case where the annular step portion 7 after welding (the annular step portion 13 before welding) is provided can be obtained.

  It should be understood that the embodiments disclosed herein are illustrative and non-restrictive in every respect. The scope of the present invention is indicated not by the above description but by the claims, and is intended to include all modifications within the meaning and scope equivalent to the claims.

  DESCRIPTION OF SYMBOLS 1 gas generator, 2 stud bolt before welding, 3 bolt part, 4 flange part, 4a outer end, 4b annular surface, 5 welding front projection part, 6 joint part, 6a outer end, 7 post welding annular step part, 8 opposed Face, 9 Weld forehead, 10 housing, 11 weld forehead, 12 weld after projection, 13 annular difference before welding, 14a, 14b top face, 15a, 15b tapered surface, 16 after weld stud bolt, 20 holder, 30 Blocking member, 31 gas jet, 40 igniter, 50 partition member, 60 chamber defining member, 70 gas generator, 80 filter, 90 housing body, DR1, DR2 axial direction, DR3 radial direction, S1 combustion chamber, S1A gas Generator storage room, S2 filter room.

Claims (10)

A housing having a substantially cylindrical outer shape;
A post-welding fixture attached to the curved outer peripheral surface of the housing;
And a joint for welding the housing and the post-welding fixture by welding by melting and solidifying a part of the pre-welding fixture;
The post-welding fixture includes a rod-like portion, and a welding back portion provided at one end of the rod-like portion and facing the outer peripheral surface of the housing via the joint portion.
The welding rear head includes a flange portion located on the rod-like portion side, and a post-welding projection portion projecting from the flange portion to the opposite side to the side where the rod-like portion is located;
The joint portion fills the space between the top surface of the projection after welding and the outer peripheral surface of the housing, and an annular portion positioned on the rod portion side of the flange portion in the axial direction of the rod portion. A gas generator located closer to the housing than a surface.   The gas generator according to claim 1, wherein the joint portion is positioned closer to the housing than the flange portion in the axial direction of the rod-like portion. The post-welding annular step defined by the flange portion and the post-welding projection portion is provided on the periphery of the welding rear portion, whereby the flange portion defines a part of the post-welding annular step portion and the housing A facing surface facing the outer circumferential surface of
The gas generator according to claim 1, wherein the joint portion is in contact with at least a part of the facing surface.   In a direction parallel to the radial direction of the rod-like portion, the outer end of the joint reaches a position inside the outer end of the flange and outside the top surface of the projection after welding The gas generator according to any one of claims 1 to 3, wherein   The gas generator according to any one of claims 2 to 4, wherein the outer diameter of the flange portion is 1.2 or more times the outer diameter of the root portion of the post-welding projecting portion. Applying a voltage to the housing and the pre-welding fixture arranged oppositely with a distance;
Bringing the housing and the pre-welding fixture close, thereby joining the housing and the pre-welding fixture by welding while maintaining a state in which voltage is applied to the housing and the pre-welding fixture. ,
The housing has a substantially cylindrical outer shape,
The pre-welding fixture includes a rod-like portion and a welding forehead provided at one end of the rod-like portion.
The welding front portion has a flange portion located on the rod-like portion side, and a welding pre-protruding portion that protrudes from the flange portion to the opposite side to the side where the rod-like portion is located.
In the step of welding the housing and the pre-welding fixture by welding, the pre-welding protrusion is locally heated by generating an electric discharge between the welding front portion and the curved outer peripheral surface of the housing. Forming a joint that joins the housing and the post-welding fixture by melting and then solidifying a part of the pre-welding protrusion by this heating;
In the step of welding the housing and the pre-welding fixture by welding, the joint portion fills the space between the top surface of the non-melted portion of the pre-welding projection and the outer circumferential surface of the housing. In addition, the housing and the attachment before welding are joined under the condition that the housing is located on the side of the housing relative to the annular surface located on the side of the rod-like portion of the flange portion in the axial direction of the rod-like portion How to make a generator.   In the step of joining the housing and the attachment before welding by welding, the housing and the attachment are welded under the condition that the joint is positioned closer to the housing than the flange in the axial direction of the rod portion. The method for manufacturing a gas generator according to claim 6, wherein joining of fixtures is performed. The welding front portion has at its periphery a pre-welding annular step defined by the flange portion and the pre-welding projection;
In the step of joining the housing and the pre-welding fixture by welding, an opposing surface of the flange portion which defines a part of the pre-welding annular step portion and faces the outer peripheral surface of the housing The method for manufacturing a gas generator according to claim 6 or 7, wherein the housing and the welding pre-welding fixture are joined under the condition of joining at least a part of.   In the direction parallel to the radial direction of the rod-like portion, the top surface of the non-melted portion of the projection before welding is inside the outer end of the flange and is outside the outer end of the flange The method for manufacturing a gas generator according to any one of claims 6 to 8, wherein the joining of the housing and the pre-welding attachment is performed under a condition that the outer position is reached.   The method for manufacturing a gas generator according to any one of claims 7 to 9, wherein the outer diameter of the flange portion is 1.2 or more times the outer diameter of the root portion of the projection before welding.

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