Method for manufacturing airbag, airbag, and vehicle seat device

Abstract

The present invention provides a manufacturing method of an air bag with excellent durability. For an air bag (40), a fusing die (60) is pressed against two sheets (41, 42) arranged in superposed relation from the direction of superposition of the sheets (41, 42), thereby forming a bag portion (45) surrounded by a fusing portion (50) extending annularly. In addition, the fusing die (60) is pressed against the outer surface (42s) of the sheet (42), thereby forming the fusing portion (50) of the two sheets (41, 42) having a fusing bead portion (80) projecting toward the inside of the bag portion (45) between the two sheets (41, 42). Furthermore, a beveled portion (75) facing the direction of superposition of the sheets (41, 42) and the direction of the inside of the bag portion (45) is provided at a position of the pressing surface (70) of the fusing die (60) relative to the sheet (42) that is farther from the fusing bead portion (80) toward the outside of the bag portion (45).

Description

Technical Field

[0001] This invention relates to a method for manufacturing an air bag, an air bag, and a vehicle seat assembly. Background Technology

[0002] Conventionally, for example, as shown in Patent Document 1, there are vehicle seat devices configured such that an air bag located on the inner side of the seat cover expands and contracts to provide a relaxing effect desired by the passenger sitting in the seat. Furthermore, in such vehicle seats, for example, as shown in Patent Document 2, there are air bags having a bag portion formed by two sheets of material being bonded together. Moreover, using such an air bag simplifies the structure.

[0003] Patent Document 1: Japanese Patent No. 4305663

[0004] Patent Document 2: Japanese Patent Application Publication No. 2015-96403

[0005] However, in the aforementioned airbag design, where air is filled into the bag to expand it, stress tends to concentrate at the joints of the sheets, i.e., the periphery of the bag. Therefore, if excessive load is applied to the bag, a fracture may form at the periphery, thus there is room for improvement in this design. Summary of the Invention

[0006] This invention was made to solve the above-mentioned problems, and its purpose is to provide a method for manufacturing an air bag with excellent durability, an air bag, and a vehicle seat device.

[0007] The method for manufacturing an air bag that solves the above-mentioned problem includes the following steps: pressing a welding mold against two overlapping sheets from the overlapping direction of each sheet to form a bag portion surrounded by a ring-shaped welding portion; the welding mold pressing against the sheets to form the welding portion having a welding weld bead protruding from between the two sheets toward the inside of the bag portion; and in the pressing surface of the welding mold against the sheets, a beveled surface is provided at a position on the outside of the bag portion, which is closer to the overlapping direction of the sheets and the direction that becomes the inside of the bag portion.

[0008] That is, a fusion portion of two sheets is formed at the pressing position of the fusion die, thereby forming a bag portion whose periphery is surrounded by the fusion portion. Furthermore, at this time, the material of the sheets pressed down by the fusion die moves along the surface direction of each sheet towards the inside of the bag portion, thereby forming a fusion weld bead protruding towards the inside of the bag portion. Moreover, according to the above structure, the material of the sheets pressed down by the fusion die moves along the inclined portion provided on the pressing surface. As a result, the thickness of the fusion portion near the base end of the fusion weld bead along the surface direction of each sheet becomes thicker. That is, the wall thickness of the easily fractured portion of the fusion portion starting from the base end of the fusion weld bead becomes thicker. Therefore, the rupture of the bag portion due to the fracture of the fusion portion becomes less likely to occur, thereby improving the durability of the air bag.

[0009] In the method for manufacturing an air bag that solves the above-mentioned problems, it is preferable that the aforementioned inclined portion has a convex curved surface shape.

[0010] Based on the above structure, the wall thickness of the part that is prone to breakage in the welded section can be increased more effectively.

[0011] In the method for manufacturing an air bag that solves the above-mentioned problem, it is preferable that the aforementioned beveled portion is formed by chamfering the corner formed by the aforementioned pressing surface and the side wall of the aforementioned fusion mold that intersects with the pressing surface.

[0012] Based on the above structure, a beveled surface can be easily formed on the welding die at a position on the outer side of the bag portion, closer to the formation position of the welding bead portion, facing the overlapping direction of each sheet and the direction that becomes the inner side of the bag portion.

[0013] In the method for manufacturing an air bag that solves the above-mentioned problems, it is preferable that the aforementioned fusion mold is provided as the aforementioned pressing surface: a first pressing surface, which is pressed against the outer surface of the aforementioned sheet; and a second pressing surface, which is pressed against the outer surface of the aforementioned sheet at a position that is retracted from the aforementioned first pressing surface in the pressing direction of the aforementioned fusion mold, and the aforementioned inclined portion is provided at the boundary between the aforementioned second pressing surface and the side wall surface of the aforementioned fusion mold that intersects with the aforementioned second pressing surface.

[0014] According to the above structure, a first weld bead is formed at the position where the first pressing surface presses, on the outer side of the bag portion. Furthermore, a second weld bead is formed at the position where the second pressing surface presses, bulging outwards from the weld bead formed on the inner side of the bag portion. Therefore, the thickness of the weld bead in the overlapping direction of each sheet can be increased near the base end of the weld bead.

[0015] Furthermore, the material of the sheet pressed down by the second pressing surface moves along the inclined surface towards the boundary between the second pressing surface and the side wall of the welding mold, thereby filling the boundary between the second weld portion and the connection end of the sheet to which the second weld portion is connected. This second weld portion is formed between the weld bead portion and the first weld portion. Furthermore, by filling the boundary between the second weld portion and the connection end of the sheet, an inclined surface is formed that connects the outer surface of the second weld portion and the outer surface of the sheet. As a result, the thickness of the weld portion near the base end of the weld bead portion along the surface direction of each sheet becomes thicker. Therefore, breakage of the weld portion starting from the base end of the weld bead portion becomes less likely to occur, thereby improving the durability of the air bag.

[0016] Based on the method for manufacturing an air bag that solves the above-mentioned problems, it is preferable that the aforementioned fusion molding die has a second inclined portion disposed at the boundary between the aforementioned first pressing surface and the aforementioned second pressing surface.

[0017] Based on the above structure, the rupture of the bag portion caused by the breakage of the welded portion becomes even less likely to occur. Therefore, the durability of the air bag can be improved.

[0018] In the method for manufacturing an air bag that solves the above-mentioned problems, it is preferable that the aforementioned fusion mold has a recess formed on the aforementioned pressing surface.

[0019] According to the above structure, the amount of sheet material that moves to the inner side of the bag section due to being depressed by the welding mold is reduced. Furthermore, the amount of protrusion into the inner side of the bag section for the weld bead formed between the two sheets is reduced. As a result, stress becomes less likely to concentrate at the base end of the weld bead. Consequently, breakage of the weld bead becomes less likely, thereby improving the durability of the air bag.

[0020] The preferred method for manufacturing an air bag that solves the above-mentioned problem is to use a first and a second welding mold that clamps the sheets in the overlapping direction of the sheets to form the welding portion surrounding the bag portion.

[0021] According to the above structure, the two sheets that form the base material of the bag portion can be welded together more reliably. Furthermore, on both sides of the overlapping direction of each sheet, the thickness of the weld portion near the base end of the weld bead along the surface direction of each sheet increases. Therefore, breakage of the weld portion originating from the base end of the weld bead becomes less likely to occur, thereby improving the durability of the air bag.

[0022] The air bag that solves the above-mentioned problem has a bag portion surrounded by an annular welded portion formed by two sheets that are welded together. The welded portion has: a first welded portion formed at a position that is the outer side of the bag portion; a weld bead formed between the two sheets in a state that protrudes inward toward the bag portion; a second welded portion formed between the weld bead and the first welded portion in a state that bulges outward toward the bag portion; and a filling portion that fills the boundary between the second welded portion and the connection end of the sheet connected to the second welded portion at the outer side of the bag portion, thereby forming an inclined surface that connects the outer surface of the second welded portion and the outer surface of the sheet in the overlapping direction of the sheets.

[0023] According to the above structure, the thickness of the weld bead in the overlapping direction of each sheet can be increased near the base end of the weld bead. Furthermore, the thickness of the weld bead along the surface direction of each sheet near the base end of the weld bead becomes increased. As a result, breakage of the weld bead originating from the base end of the weld bead becomes less likely to occur. Therefore, the durability of the air bag can be improved.

[0024] In the air bag that solves the above-mentioned problem, it is preferable that the aforementioned welded portion has a second filling portion, which fills the boundary between the aforementioned first welded portion and the aforementioned second welded portion to form a second inclined surface that connects the outer surface of the aforementioned first welded portion and the outer surface of the aforementioned second welded portion.

[0025] Based on the above structure, the rupture of the bag portion caused by the breakage of the welded portion becomes even less likely to occur. Therefore, the durability of the air bag can be improved.

[0026] The air bag that solves the above problem preferably has a protruding part on the outer surface of the aforementioned first welded part.

[0027] According to the above structure, when the weld bead is formed using a welding die, the amount of sheet material that moves to the inner side of the bag portion due to being pressed down by the welding die is reduced. Furthermore, the amount of protrusion into the inner side of the bag portion for the weld bead formed between the two sheets is reduced. As a result, stress becomes less likely to concentrate at the base end of the weld bead. Consequently, breakage of the weld bead becomes less likely, thereby improving the durability of the air bag.

[0028] In the air bag that solves the above problems, it is preferable that the aforementioned welded portion has the aforementioned second welded portion and the aforementioned inclined surface on both sides of the overlapping direction of the aforementioned sheets.

[0029] Based on the above structure, breakage of the weld portion originating from the base end of the weld bead becomes less likely to occur on both sides of the overlapping direction of each sheet. Therefore, the durability of the air bag can be improved.

[0030] The vehicle seat device that solves the above problems has an air bag as described in any of the above items.

[0031] Based on the above structure, higher reliability can be ensured through improved durability.

[0032] According to the present invention, the durability of air bags can be improved. Attached Figure Description

[0033] Figure 1 This is a 3D diagram of a vehicle seat with air pockets on the inside of the seat cover.

[0034] Figure 2 This is a 3D diagram of a vehicle seat with air pockets on the inside of the seat cover.

[0035] Figure 3 This is a schematic diagram of the seat assembly.

[0036] Figure 4 This is a top view of the air bag.

[0037] Figure 5 This is a cross-sectional view of the air bag.

[0038] Figure 6 This is a cross-sectional view showing the manufacturing process of an air bag.

[0039] Figure 7 This is a cross-sectional view showing the manufacturing process of an air bag.

[0040] Figure 8 This is a cross-sectional view showing the manufacturing method of the comparative example air bag.

[0041] Figure 9 This is a cross-sectional view of the vicinity of the welded portion formed using the weld die of the comparative example.

[0042] Figure 10 It is a cross-sectional view of the vicinity of the welded area formed using a welding die.

[0043] Figure 11 This is a cross-sectional view showing the manufacturing method of an air bag in other examples.

[0044] Figure 12 This is a cross-sectional view showing the manufacturing method of an air bag in other examples.

[0045] Figure 13 This is a cross-sectional view showing the manufacturing method of an air bag in other examples.

[0046] Explanation of reference numerals in the attached figures

[0047] 40…Air bag; 41, 42…Sheet; 42s…Outer surface; 45…Bag section; 50…Welding section; 60…Welding mold; 70…Pressing surface; 75…Beveled section; 80…Welding weld section. Detailed Implementation

[0048] Hereinafter, an embodiment of the air bag and vehicle seat device will be described with reference to the accompanying drawings.

[0049] like Figure 1 and Figure 2 As shown, the vehicle seat 1 includes a seat cushion 2 and a seat back 3 located at the rear end of the seat cushion 2. Furthermore, a headrest 4 is provided at the upper end of the seat back 3.

[0050] Furthermore, in the seat 1 of this embodiment, the seat back 3 has a shape in which its two sides 3a and 3b bulge forward. Also, the seat cushion 2 has a shape in which its two sides 2a and 2b bulge upward. Thus, the seat 1 of this embodiment is able to ensure and maintain a good seating posture for the passenger.

[0051] Furthermore, the seat 1 is provided with multiple air pockets 10 that expand and contract inside the seat cushion 2 and seat back 3 to change the support shape of the seat 1. Similarly, the seat 1 is also provided with multiple air pockets 20 that expand and contract inside the seat cushion 2 and seat back 3 to press the seat surface 1x from the inside. Thus, in this embodiment, a seat device 30 capable of changing the support shape of the seat 1 and providing a relaxing effect for the passenger seated in the seat 1 is formed.

[0052] Specifically, in the seat 1 of this embodiment, individual air bags 10 for seat support are provided on the inner side of the seat back 3 at positions corresponding to the shoulder, waist, and lower end of the seat back 3s. These air bags 10 are sometimes referred to as the shoulder, waist, and pelvic area, respectively. Additionally, individual air bags 10 for seat support are also provided on the seat back 3 at positions corresponding to the two sides 3a and 3b. Furthermore, for the seat cushion 2, individual air bags 10 for seat support are also provided on the inner side of the rear end of its seating surface 2s and on the inner sides of the two sides 2a and 2b.

[0053] Furthermore, multiple relaxation airbags 20 are provided on the inner side of the seat back 3, arranged along the back 3s. Similarly, multiple massage airbags 20 are provided on the seat cushion 2, arranged along the seating surface 2s. Specifically, the airbags 20 on the side of the seat back 3 are arranged in two rows along the vertical direction of the back 3s. Likewise, the airbags 20 on the side of the seat cushion 2 are also arranged in two rows along the front-back direction of the seating surface 2s.

[0054] like Figure 3 As shown, the seat assembly 30 of this embodiment includes an air pump 31 that pressurizes air to each of the air bags 10 for seat support and each of the air bags 20 for massage. Furthermore, an air supply / exhaust valve device 32 is sandwiched between the air pump 31 and each of the air bags 10 and 20. Moreover, in the seat assembly 30 of this embodiment, the operation of the air pump 31 and the air supply / exhaust valve device 32 is controlled by a control device 33.

[0055] Specifically, in the air pump 31 of this embodiment, an electric pump driven by a motor 34 is used. Furthermore, the supply and exhaust valve device 32 is connected to each air bag 20 and the air pump 31 via a flexible resin air tube 35. That is, in the seat device 30 of this embodiment, an air flow path, i.e., a supply and exhaust flow path Lo, is formed through the internal passages of these air tubes 35 and the supply and exhaust valve device 32, connecting each air bag 10, 20 to the air pump 31. Moreover, the supply and exhaust valve device 32 of this embodiment is thus configured such that its supply valve 36 and exhaust valve 37 are disposed midway along the supply and exhaust flow path Lo.

[0056] In addition, operation input signals Scr, ignition signals Sig, or door lock signals Sdl, etc., are input to the control device 33 of this embodiment for the operation switch 38 provided on the seat 1. Thus, the control device 33 of this embodiment is configured to control the operation of the air pump 31 and the air supply and exhaust valve device 32 based on these control signals, so as to cause the air bags 10, 20 to expand and contract.

[0057] In detail, the control device 33 of this embodiment detects the internal pressure P of each air bag 10 used for seat support and maintains a target value for its internal pressure P. Furthermore, this target internal pressure value is updated by the user using the operation switch 38 provided on the seat 1 to set the optimal seat support shape. Therefore, the control device 33 of this embodiment is configured to control the operation of the air pump 31 and the air supply / exhaust valve device 32 when the vehicle is started, for example, when the IG is turned on, so that the internal pressure P of each air bag 10 matches the target internal pressure value, thereby causing each air bag 10 used for seat support to expand.

[0058] Furthermore, the control device 33 of this embodiment switches to the expanded state of each massage air bag 20 based on a predetermined operating mode. Thus, the seat device 30 of this embodiment can achieve the relaxation effect desired by the passenger seated in the seat 1.

[0059] (Air bag)

[0060] Next, the structure of the air bag used in the seat device 30 of this embodiment and its manufacturing method will be described.

[0061] like Figure 4 and Figure 5 As shown, in the seat assembly 30 of this embodiment, the air bags 40 used for each air bag 10 for seat support and each air bag 20 for massage each have a bag portion 45 formed by bonding two sheets 41 and 42. Furthermore, in Figure 4 The document describes an example where the planar shape of the air bag 40 is simplified. That is, the air bag 40 expands by filling air between the two sheets 41, 42 that form the bag portion 45. Thus, the seat device 30 of this embodiment is configured such that the bag portions 45 of each expanded air bag 40 press against the seat surface 1x from the inside.

[0062] In the seat assembly 30 of this embodiment, the sheets 41 and 42 constituting the air bag 40 are made of a flexible resin material such as vinyl chloride. Furthermore, a high-frequency welding method is used, for example, in the welding of these sheets 41 and 42. Therefore, in Figure 4 and Figure 5 The fused portions 50 of the two sheets 41 and 42 sealing the periphery of the bag portion 45 are shown by shading.

[0063] In addition, such as Figure 6 and Figure 7 As shown, the air bag 40 is formed by pressing the fusion mold 60 against two sheets 41, 42 that overlap in the thickness direction from their overlapping direction.

[0064] Specifically, in this embodiment, the welding die 60 presses down on two sheets 41 and 42 that are stacked on the worktable 61 from above. As a result, at the location pressed by the welding die 60, the sheet 42 that overlaps the sheet 41, i.e., the sheet 42 whose outer surface is pressed by the welding die 60, melts. Furthermore, at the location pressed by the welding die 60, including the boundary with the sheet 42, the sheet 41 located below also melts; however, for ease of explanation, [the specific details are not provided in the original text]. Figure 7 In the figures shown below, their illustrations are omitted. Furthermore, the portion pressed by the welding mold 60 deforms according to the cross-sectional shape of the welding mold 60. Thus, the air bag 40 of this embodiment is configured such that the welding mold 60 is then lifted upwards to separate it from the outer surface 42s of the sheet 42, thereby forming the welding portion 50 of the two sheets 41, 42.

[0065] Furthermore, in this embodiment, the planar shape of the pressing surface 70 of the welding mold 60 used for forming the air bag 40 is set so that a ring-shaped welding portion 50 is formed therefrom. Thus, the air bag 40 of this embodiment is configured to have a bag portion 45 surrounded by the ring-shaped welding portion 50 formed by the two mutually welded sheets 41, 42.

[0066] For example, in forming a structure with such Figure 5 In the case of the generally rectangular planar bag portion 45 shown, a welding mold 60 having a generally four-sided border-shaped pressing surface 70 surrounding the outer periphery of the bag portion 45 is pressed onto each sheet 41, 42. Thus, the air bag 40 of this embodiment is configured such that the periphery of the bag portion 45 is sealed by an annular welding portion 50 surrounding the bag portion 45.

[0067] Furthermore, for ease of explanation, in Figure 6 and Figure 7 Only the cross-section orthogonal to the pressing surface 70 of the welding mold 60 is shown. Furthermore, the cross-sectional shape of the welding mold 60 in this embodiment is symmetrical, therefore, in each figure, the welding portion 50 can seal between the two sheets 41 and 42, which extend laterally along the center line orthogonal to the pressing surface 70. Thus, in this embodiment, the air bag 40 is configured such that a bag portion 45 is formed on the right side of the welding portion 50 in each figure.

[0068] In further detail, the fusion molding die 60 used in forming the air bag 40 of this embodiment has a first pressing surface 71 that presses against the outer surface 42s of the sheet 42, serving as its pressing surface 70. In the fusion molding die 60 of this embodiment, the first pressing surface 71 is a flat surface that is pressed in a state that is substantially parallel to the outer surface 42s of the sheet 42. Furthermore, the fusion molding die 60 of this embodiment has a second pressing surface 72 that presses against the outer surface 42s of the sheet 42 at a position that is retracted from the first pressing surface 71 in the pressing direction, that is, at a position above the first pressing surface 71 in each figure.

[0069] Furthermore, in the welding mold 60 of this embodiment, the corner 74 formed by the second pressing surface 72 and the side wall surface 73 intersecting the second pressing surface 72 is chamfered. Specifically, in this embodiment, the corner 74 is chamfered to make it a so-called "rounded surface", that is, a convex curved surface shape. Thus, the welding mold 60 of this embodiment is configured such that the boundary portion α between these second pressing surfaces 72 and the side wall surface 73 has a beveled portion 75 that faces the overlapping direction of each sheet 41, 42 (lower side in each figure) and becomes the inner side of the pocket portion 45 formed by these sheets 41, 42 (right side in each figure) when facing the outer surface 42s of the sheet 42.

[0070] That is, in this embodiment, the fusion molding die 60 presses two sheets 41 and 42 between its pressing surface 70 and the placement surface 61s of the worktable 61 onto the outer surface 42s of the sheet 42, thereby pressing towards the side wall surface 73. Figure 7The molten resin component, mainly the material of sheet 42, is pressed down in the middle (left and right directions) to form the welded portion 50. Thus, in the air bag 40 of this embodiment, the welded portion 50 has a welded bead 80 protruding inward from the bag portion 45 between the two sheets 41 and 42.

[0071] Specifically, in this embodiment, the portion of the welding mold 60 between its most prominent first pressing surface 71 and the placement surface 61s of the worktable 61, which has the same flat surface shape as its first pressing surface 71, forms the overlapping direction of the two sheets 41, 42 as the welding portion 50. Figure 7 The first weld portion 81 is the thinnest in the vertical direction. Furthermore, the weld mold 60 of this embodiment forms a second weld portion 82, which bulges outward from the bag portion 45 and is continuous with the weld bead portion 80. That is, in the weld portion 50 of this embodiment, the first weld portion 81 is formed at a position that forms the outer side of the bag portion 45. The second weld portion 82 has a thickness greater than that of the first weld portion 81 in the overlapping direction and is formed between the first weld portion 81 and the weld bead portion 80. Thus, the air bag 40 of this embodiment is configured such that a sheet 42 forming the bag portion 45 is connected to the outer surface 82s of the second weld portion 82 constituting the weld portion 50.

[0072] Here, in Figure 8 The comparative example of the welding mold 60B is illustrated below. This welding mold 60B has a corner 74 formed at the boundary α between its pressing surface 70 and the side wall surface 73, where the pressing surface 70 and the side wall surface 73 intersect at approximately right angles. That is, the comparative example of the welding mold 60B does not employ the chamfering treatment found in the welding mold 60 of this embodiment.

[0073] Therefore, as Figure 8 and Figure 9 As shown, in the welded portion 50B of the air bag 40B formed using the weld die 60B, an angle 84 is easily formed at the boundary portion β of the second welded portion 82 formed on the outer side of the bag portion 45 and the connecting end 42a of the sheet 42 connected to the second welded portion 82. That is, the angle 84 of the boundary portion β is a concave shape corresponding to the corner portion 74 of the weld die 60B.

[0074] In contrast, such as Figure 7 and Figure 10 As shown, the air bag 40 formed using the welding mold 60 of this embodiment has a welded portion 50 with an inclined surface 85 on the outside of the bag portion 45. The inclined surface 85 connects the outer surface 82s of the second welded portion 82 facing the overlapping direction of the two sheets 41 and 42, and the outer surface 42s of the sheet 42 pressed by the welding mold 60.

[0075] That is, in the welding mold 60 of this embodiment, as described above, the corners 74 formed by the pressing surface 70 and the side wall surface 73 are chamfered, thereby forming a beveled portion 75 at the boundary α between these pressing surfaces 70 and the side wall surface 73. Thus, the welding portion 50 of the air bag 40 formed using the welding mold 60 is configured to form a beveled portion 85 corresponding to the beveled portion 75 of the welding mold 60.

[0076] That is, in this embodiment, the welding mold 60 is configured such that pressing is performed by the pressing surface 70, specifically the first pressing surface 71 and the second pressing surface 72 of the welding mold 60, thereby causing the material of the sheet 42, which is pressed back by the side wall surface 73, to move along the inclined surface 75 to the boundary α between the side wall surface 73 and the second pressing surface 72 of the welding mold 60. In addition, as a result, in the welding portions 50 of the two sheets 41 and 42, the boundary β between the second welding portion 82 and the connecting end 42a of the sheet 42 connected to the second welding portion 82 is filled, and the second welding portion 82 is formed between the welding bead portion 80 and the first welding portion 81 in a state of bulging outward from the bag portion 45. Therefore, in the air bag 40 of this embodiment, a filling portion 86 is formed by filling the boundary portion β of the connection end 42a of the second welded portion 82 and the sheet 42, thereby forming an inclined surface 85 that connects the outer surface 82s of the second welded portion 82 and the outer surface 42s of the sheet 42.

[0077] Next, the function of this embodiment will be explained.

[0078] That is, for two sheets 41 and 42 that overlap in the thickness direction, the welding die 60 presses them from the overlapping direction to form the welding portion 50 of these two sheets 41 and 42. Then, the planar shape of the pressing surface 70 of the welding die 60 is set in such a way that the welding portion 50 is formed in a ring shape, so that the bag portion 45 of the air bag 40 is formed in a state where the periphery is sealed by the welding portion 50.

[0079] Furthermore, the welded portion 50 formed using such a weld die 60 has a weld bead 80 protruding inwards from the two sheets 41, 42 forming the bag portion 45. Therefore, it is structured such that, for example, in cases where excessive load is applied to the expanded bag portion 45, stress tends to concentrate at the base end 80b of the weld bead 80. Thus, it is possible to extend the weld bead 80 from the base end 80b toward the outer side of the bag portion 45 along the surface direction of each sheet 41, 42. Figure 9 and Figure 10 The bag portion 45 breaks in a manner that occurs in the middle (left and right directions) and the welded portion 50 breaks.

[0080] However, by using the welding mold 60 of this embodiment, the thickness D of the weld portion 50 near the base end 80b of the weld bead 80 along the surface direction of each sheet 41, 42 becomes thicker (D1 > D0). As a result, it becomes less likely for the bag portion 45 to break due to the breakage of the weld portion 50, thereby improving the durability of the air bag 40.

[0081] Next, the effects of this implementation method will be explained.

[0082] (1) For the air bag 40, the welding mold 60 presses the two overlapping sheets 41 and 42 from the overlapping direction of each sheet 41 and 42 to form a bag portion 45 surrounded by the annularly extending welding portion 50. In addition, the welding mold 60 presses the outer surface 42s of the sheet 42 to form the welding portion 50 of the two sheets 41 and 42 having a welding bead portion 80 protruding towards the inside of the bag portion 45 between the two sheets 41 and 42. Moreover, in the pressing surface 70 of the welding mold 60 on the sheet 42, a beveled portion 75 is provided at a position closer to the outside of the bag portion 45 than the formation position of the welding bead portion 80, facing the overlapping direction of each sheet 41 and 42 and the direction that becomes the inside of the bag portion 45.

[0083] That is, at the position pressed by the pressing surface 70 of the welding die 60, welding portions 50 of two sheets 41 and 42 are formed, thereby forming a pouch portion 45 whose periphery is surrounded by the welding portions 50. Furthermore, at this time, the material of the sheet 42, which is pressed back by the pressing surface 70 of the welding die 60, moves along the surface direction of each sheet 41 and 42 to a position that becomes the inner side of the pouch portion 45, thereby forming a weld bead portion 80 protruding inwards from the pouch portion 45. Moreover, according to the above configuration, the material of the sheet 42, which is pressed back by the welding die 60, moves along the inclined portion 75 provided on its pressing surface 70. As a result, the thickness D of the welding portion 50 near the base end portion 80b of the weld bead portion 80 along the surface direction of each sheet 41 and 42 becomes thicker. That is, the wall thickness of the easily fractured portion of the welding portion 50 starting from the base end portion 80b of the weld bead portion 80 becomes thicker. Therefore, it becomes less likely that the bag portion 45 will break due to the breakage of the welded portion 50, thereby improving the durability of the air bag 40.

[0084] (2) The inclined surface 75 has a convex curved surface shape. As a result, the wall thickness of the part of the welded portion 50 that is prone to breakage can be increased more effectively.

[0085] (3) The beveled portion 75 is formed by chamfering the corner 74 formed by the pressing surface 70 of the fusion mold 60 and the side wall surface 73 of the fusion mold 60 that intersects with the pressing surface 70.

[0086] Based on the above configuration, a beveled portion 75 can be easily formed on the deposition mold 60 at a position on the outer side of the bag portion 45, which faces the overlapping direction of each sheet 41, 42 and becomes the inner side of the bag portion 45, with a simple structure.

[0087] (4) The welding die 60 includes, as its pressing surface 70, a first pressing surface 71 that presses against the outer surface 42s of the sheet 42; and a second pressing surface 72 that presses against the outer surface 42s of the sheet 42 at a position that is retracted from the first pressing surface 71 in the pressing direction of the welding die 60. Furthermore, a beveled portion 75 is provided at the boundary α between the second pressing surface 72 and the side wall surface 73 of the welding die 60 that intersects with the second pressing surface 72.

[0088] According to the above structure, a first weld bead portion 81 is formed at the position where the first pressing surface 71 presses, on the outer side of the bag portion 45. Furthermore, a second weld bead portion 82 is formed at the position where the second pressing surface 72 presses, protruding from the weld bead portion 80 formed on the inner side of the bag portion 45 towards the outer side of the bag portion 45. Therefore, the thickness of the weld bead portion 50 in the overlapping direction of the sheets 41 and 42 can be increased near the base end portion 80b of the weld bead portion 80.

[0089] Furthermore, the material of the sheet 42, which is pressed back by the second pressing surface 72, moves along the inclined surface 75 to the boundary α between the second pressing surface 72 and the side wall surface 73 of the welding mold 60, thereby filling the boundary β between the second welding portion 82 and the connecting end 42a of the sheet 42 connected to the second welding portion 82. The second welding portion 82 is formed between the welding bead portion 80 and the first welding portion 81. Moreover, by filling the boundary β between the second welding portion 82 and the connecting end 42a of the sheet 42, an inclined surface 85 is formed that connects the outer surface 82s of the second welding portion 82 and the outer surface 42s of the sheet 42. As a result, the thickness D of the welding portion 50 near the base end 80b of the welding bead portion 80 along the surface direction of each sheet 41, 42 becomes thicker. Therefore, it becomes difficult for the welded portion 50, which starts from the base end 80b of the welded portion 80, to break, thereby improving the durability of the air bag 40.

[0090] Furthermore, the above-described embodiments can be implemented in the following ways. The above-described embodiments and the following modifications can be combined with each other within the scope of technical non-contradiction.

[0091] In the above embodiment, the seat device 30 provided in the seat 1 of the vehicle is specifically defined as the air bag 40 used by each air bag 10 for seat support and each air bag 20 for massage, but it can also be applied to air bags used for purposes other than seat device 30.

[0092] Furthermore, as long as the welding mold 60 can be used to form the welding portion 50, the material of each sheet 41, 42 constituting the air bag 40 can be arbitrarily changed. Moreover, the planar shape of the bag portion 45 surrounded by the ring-shaped welding portion 50 can also be arbitrarily changed.

[0093] • The planar shape of the pressing surface 70 in the welding mold 60 does not necessarily have to be a ring shape. That is, the ring-shaped welding portion 50 that surrounds the entire circumference of the bag portion 45 does not necessarily have to be formed by a single pressing operation; it can also be configured to form the ring-shaped welding portion 50 by multiple pressing operations. Furthermore, the periphery of the bag portion 45 can be sealed not only by the welding process based on the pressing of the welding mold 60, but also by sealing the gap left by inserting the air pipe 35, which constitutes the air supply and exhaust flow path Lo, thereby completing the bag portion 45.

[0094] In the above embodiment, the fusion mold 60 has a first pressing surface 71 and a second pressing surface 72 that is recessed from the first pressing surface 71 as its pressing surface 70. Furthermore, the beveled portion 75 has a convex curved surface shape by chamfering the corner 74 formed by the second pressing surface 72 and the side wall surface 73 of the fusion mold 60, and is provided at the boundary α between the second pressing surface 72 and the side wall surface 73. However, it is not limited to this; the beveled portion 75 may not necessarily be a convex curved surface shape. For example, the chamfering treatment of the corner 74 may be a "corner surface" treatment instead of a so-called "round surface" treatment.

[0095] Additionally, such as Figure 11 As shown, it can also be configured to use a welding mold 60C having a second inclined portion 90 provided at the boundary portion γ of the first pressing surface 71C and the second pressing surface 72C to form a welding portion 50C surrounding the bag portion 45 of the air bag 40C.

[0096] Specifically, in this other example of the welding mold 60C, the second beveled portion 90 is formed by chamfering the corner 94 formed by the second side wall surface 93 of the welding mold 60 and its first pressing surface 71C. The second side wall surface 93 of the welding mold 60 is formed by the first pressing surface 71C and the second pressing surface 72C arranged in a stepped manner. Furthermore, the welding portion 50C formed using this welding mold 60C includes a second filling portion 95 that fills the boundary δ between the first welding portion 81C and the second welding portion 82C. The second filling portion 95 also forms a second bevel 96 connecting the outer surface 81s of the first welding portion 81C and the outer surface 82s of the second welding portion 82C. As a result, the rupture of the bag portion 45 caused by the breakage of the welding portion 50C becomes even more difficult to occur. Therefore, the durability of the air bag 40 can be improved.

[0097] Additionally, such as Figure 12 As shown, a welding mold 60D with a recess 97 on the pressing surface 70 can also be used to form a welding portion 50D surrounding the bag portion 45 of the air bag 40D. Specifically, in this other example of the welding mold 60D, the recess 97 is formed on the first pressing surface 71D. Furthermore, the formation position of the recess 97 in the pressing surface 70 can be arbitrarily changed. Thus, the welding portion 50D formed using the welding mold 60D has a protruding protrusion 98 on the outer surface 81s of the first welding portion 81D.

[0098] That is, by using a welding die 60D of this other example, the amount of material in the sheet 42 that moves toward the inside of the bag portion 45 due to being pressed back by the welding die 60 is reduced. Furthermore, the amount of protrusion toward the inside of the bag portion 45 for the weld bead 80 formed between the two sheets 41 and 42 is reduced. As a result, stress becomes less likely to concentrate at the base end 80b of the weld bead 80. Consequently, breakage of the weld portion 50D becomes less likely, thereby improving the durability of the air bag 40.

[0099] ·And, as Figure 13 As shown, it can also be configured to use first and second welding molds 60Ea and 60Eb to clamp the sheets 41 and 42 in the overlapping direction of the sheets 41 and 42 as the parent material, thereby forming a welding portion 50E surrounding the bag portion 45.

[0100] Specifically, these first and second deposition molds 60Ea and 60Eb have the same cross-sectional shape as the deposition mold 60 in the above embodiment (see reference). Figure 6 and Figure 7That is, these first and second welding molds 60Ea and 60Eb have pressing surfaces 70 and 70 that are symmetrical to each other across the sheets 41 and 42. Thus, in this example, the first welding mold 60Ea presses the outer surface 41s of the lower sheet 41 from below, and the second welding mold 60Eb presses the outer surface 42s of the upper sheet 42 from above, thereby forming the welding portion 50E.

[0101] That is, in the air bag 40E of this other example, the first weld portion 81E of the weld portion 50E is formed by being clamped between the first pressing surfaces 71, 71 of the first and second weld dies 60Ea, 60Eb. Furthermore, the second weld portion 82E is formed by being clamped between second pressing surfaces 72, 72 that are separated from these first pressing surfaces 71, 71 in their vertical direction, i.e., the overlapping direction of the sheets 41, 42. Thus, the material of each sheet 41, 42, which is pressed back by the pressing surfaces 70, 70 of the first and second weld dies 60Ea, 60Eb, moves towards the inside of the bag portion 45, thereby forming a weld bead portion 80 protruding inwards from the bag portion 45.

[0102] Furthermore, based on the shape of the inclined portions 75 and 75 of the pressing surfaces 70 and 70 of the first and second welding molds 60Ea and 60Eb, filling portions 86 and 86 are formed to fill the boundary portions ε and ε of the second welding portion 82E and 82E and the connecting ends 41a and 42a of the sheets 41 and 42. Thus, through these filling portions 86 and 86, inclined surfaces 85 and 85 are formed to connect the outer surfaces 82s and 82s of the second welding portion 82 and the outer surfaces 41s and 42s of the sheets 41 and 42, respectively.

[0103] According to the above structure, the two sheets 41 and 42, which serve as the base material for the bag portion 45, can be welded more reliably. Furthermore, on both sides of the overlapping direction of each sheet 41 and 42, the thickness D of the weld portion 50E near the base end 80b of the weld bead 80 along the surface direction of each sheet 41 and 42 increases. Therefore, the weld portion 50E starting from the base end 80b of the weld bead 80 becomes less prone to breakage, thereby improving the durability of the air bag 40.

[0104] Furthermore, it is also possible to configure at least one of the first and second caulking molds 60Ea and 60Eb to have a second inclined portion 90, a recess 97, or both, as shown in the other examples above.

[0105] In addition, in the above embodiments and other examples, the fusion mold 60 has a cross-sectional shape that is symmetrical about the center line when a center line orthogonal to its pressing surface 70 is drawn out, but it may not necessarily have such a line-symmetrical cross-sectional shape.

[0106] In the above embodiments and other examples, the welding mold 60 has a first pressing surface 71 and a second pressing surface 72 that is recessed from the first pressing surface 71 as its pressing surface 70, but it may also have a structure without the second pressing surface 72. That is, it may also have a structure in which a beveled portion 75 is formed at the boundary between the pressing surface 70 without a step difference and the side wall surface 73 of the welding mold 60 that intersects with the pressing surface 70. Moreover, the beveled portion 75 may be formed by a method other than chamfering.

[0107] In the above embodiments, high-frequency welding was exemplified as an example of a welding method using the welding mold 60, but a hot welding method that heats the welding mold 60 can also be used.

Claims

1. A method for manufacturing an air bag, characterized in that, The process includes pressing a welding die against two overlapping sheets in the overlapping direction of each sheet to form a bag portion surrounded by a ring-shaped welding portion. The welding die is pressed against the sheet material to form a weld bead between the two sheets that protrudes inward toward the inside of the bag portion. On the pressing surface of the welding die against the sheet, at a position further outward from the location where the weld bead is formed, there is a beveled portion facing the overlapping direction of the sheets and the direction that becomes the inner side of the bag portion. The caulking die has a recess formed on the pressing surface.

2. The method for manufacturing an air bag according to claim 1, characterized in that, The beveled portion has a convex curved surface shape.

3. The method for manufacturing an air bag according to claim 1 or 2, characterized in that, The beveled portion is formed by chamfering the corner formed by the pressing surface and the side wall of the fusion mold that intersects with the pressing surface.

4. The method for manufacturing an air bag according to claim 1 or 2, characterized in that, The pressing surface of the welding mold includes: The first pressing surface is pressed against the outer surface of the sheet; and The second pressing surface presses against the outer surface of the sheet at a position retracted from the first pressing surface in the pressing direction relative to the welding mold. The inclined portion is located at the boundary between the second pressing surface and the side wall of the welding mold that intersects with the second pressing surface.

5. The method for manufacturing an air bag according to claim 4, characterized in that, The caulking die has a second inclined portion disposed at the boundary between the first pressing surface and the second pressing surface.

6. The method for manufacturing an air bag according to claim 1 or 2, characterized in that, The welded portion surrounding the bag portion is formed by using the first and second weld-coating dies that clamp the sheets in the overlapping direction of the sheets.

7. An air bag, characterized in that, It has a bag portion surrounded by a ring-shaped welded section formed by two sheets that are welded together. The welding section includes: The first welded portion is formed at a position that becomes the outer side of the bag portion; A weld bead is formed between the two sheets in a manner that protrudes inward toward the inside of the bag portion; The second weld bead is formed in a state that bulges outward from the bag portion at the position between the weld bead portion and the first weld bead. as well as The filling section fills the boundary between the second welded portion and the connecting end of the sheet connected to the second welded portion on the outer side of the bag portion, thereby forming an inclined surface that connects the outer surface of the second welded portion facing the overlapping direction of each sheet and the outer surface of the sheet. The outer surface of the first welded portion has a protruding protrusion.

8. The air bag according to claim 7, characterized in that, The bonding portion includes a second filling portion, which fills the boundary between the first bonding portion and the second bonding portion, thereby forming a second inclined surface that connects the outer surface of the first bonding portion and the outer surface of the second bonding portion.

9. The air bag according to claim 7 or 8, characterized in that, The fusion-coated portion has the second fusion-coated portion and the inclined surface on both sides of the overlapping direction of each sheet.

10. A vehicle seat assembly, characterized in that, It has an air bag as described in any one of claims 7 to 9.

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