JP2010076581A - Airbag - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an airbag capable of stabilizing an inflation-completed shape of a bag body by improving a tensile strength of a tether. <P>SOLUTION: The airbag 50 includes: the bag body 51; and the tether 57 for coupling walls 52 and 53 of the bag body 51, and has a substantial plate-like shape as its inflation-completed shape. The tether 57 couples the walls 52 and 53 by sewing both ends arranged apart each other up on the respective walls 52, 53 in a width direction. The tether 57 has a folded part 72 formed by folding a tethering ground fabric 69 at both ends in a direction along sewed portions 60, 61 with the walls 52, 53. The folded part 62 is superimposed on the body 70 of the tethering ground fabric 69 over a substantially entire region in a length direction of the sewed portions 60, 61 at a portion where the sewed portions 60, 61 with the tether 57 and the walls 52, 53 are arranged. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a bag-shaped bag body that can be inflated by allowing an inflating gas to flow therein, and a tether that is disposed within the bag body and that is disposed opposite to each other of the bag body. The present invention relates to an airbag having

Conventionally, an airbag having a structure in which a tether for connecting walls constituting the bag body is arranged in the bag body is folded and stored in a steering column located in front of a passenger's knee seated on the seat. Thus, there can be mentioned a knee protection airbag that inflates the left and right knees of an occupant so as to protect the left and right knees by flowing an inflation gas into the interior. And as an airbag used for an air bag device for knee protection, a tether is arranged so as to be along the left and right directions respectively in the front and rear two places in the bag body at the time of completion of inflation, and between the tethers, There has been a configuration in which an inflator that supplies inflation gas to an airbag is disposed (see, for example, Patent Document 1).
JP 2008-114701 A

  However, in the case where the inflator is arranged between the tethers as in the conventional knee protection airbag, the inflation gas discharged from the inflator flows through the gap between the tether and the bag body, and the inflator Because the distance from is close, a large tensile force acts on the stitched area where the end of the tether is sewn to the wall, especially when using an inflator with a large output, improving the strength of the tether. There was room for improvement.

  The present invention solves the above-described problems, and an object of the present invention is to provide an airbag that can improve the tensile strength of the tether and stabilize the expansion completion shape of the bag body.

An airbag according to the present invention connects a bag-shaped bag body that can be inflated by allowing an inflating gas to flow therein, and a wall portion that is disposed in the bag body and is opposed to each other. The expansion completion shape is configured as a substantially plate shape,
The tether has a substantially belt-like shape and is configured so that both ends, which are spaced apart from each other, are sewn to the respective wall portions along the width direction using sutures, and the wall portions are connected to each other. A bag,
The tether is configured to have a folded portion formed by folding the tether base fabric on both edges of the direction side along the stitched portion with the wall portion,
The folded portion is configured to be overlapped with the main body of the tether base fabric on the thickness direction side over substantially the entire length direction of the suture portion at a portion where the suture portion between the tether and the wall portion is disposed. It is characterized by.

  In the airbag of the present invention, in the tether, the portion where the stitched portion with the wall portion of the bag main body is disposed has a thickness of the folded portion of the tether base fabric with respect to the main body of the tether base fabric over substantially the entire area. It is set as the structure piled up on the direction side. In other words, the tether is a portion where three sheets including the wall portion of the bag body overlap, and is sewn to the wall portion of the bag body. Therefore, the tether is sewn to the wall and the stitching strength of the stitched area can be increased, and the tensile strength of the tether can be increased. Therefore, even when using an inflator with a large output, the tether Even if stress concentration occurs at the stitched site between the wall and the wall, the load on the tether can be reduced (dispersed). In the airbag of the present invention, the tether has a folded portion formed by folding the tether base fabric on both edge sides in the direction side along the stitched portion with the wall portion. That is, in the airbag of the present invention, the tether base fabric ends are not arranged on both edge sides in the direction side along the stitched portion with the wall portion. Can be prevented from fraying, and the expansion completion shape of the bag body can be stabilized.

  Therefore, in the airbag of the present invention, it is possible to improve the tensile strength of the tether and stabilize the inflated complete shape of the bag body.

  Further, in the airbag of the present invention, if the tether has a two-layer structure in which the main body and the folded portion are overlapped on the thickness direction side over substantially the entire region, the tensile strength of the tether can be further improved. preferable.

Furthermore, in the airbag having the above-described configuration, the tether is provided with a reinforcing portion that can reinforce the periphery of the mounting portion that attaches the airbag to the storage site.
It is preferable that the reinforcing portion has a two-layer structure in which a member extending from the main body and a member extending only from one folded portion are stacked on the thickness direction side.

  In the airbag having the above configuration, since the tether is configured to include the reinforcing portion, it is not necessary to arrange a separate reinforcing cloth on the periphery of the mounting portion. Further, each of the reinforcing portions is a single member that occupies the entire area of the reinforcing area without being divided, and a member that extends from only one folded portion, and a member that extends only from one folded portion. Since the two-layer structure is overlapped on the direction side, sufficient tensile strength can be secured even at the periphery of the attachment portion.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the embodiment, an airbag 50 used in the knee protection airbag apparatus M will be described as an example. As shown in FIG. 1, the knee protection airbag apparatus M of the embodiment protects a knee K (KL, KR) of a driver (occupant) D seated in a driver's seat and covers the steering column 3. This is a type with a steering column that is housed on the side of the lower portion 16a in the column cover 16 that is disposed. As shown in FIGS. 2 and 3, the knee protection airbag apparatus M includes a folded airbag 50 and an inflator 34 that supplies inflation gas to the airbag 50 on the lower portion 16 a side in the column cover 16. It is configured to be housed in the provided storage site P (see FIGS. 2 and 3).

  In the present specification, the front and rear, top and bottom, and left and right directions are based on the axial direction of the steering column 3 unless otherwise specified, and the direction along the axial direction of the steering column 3 is the front and rear direction. The vertical direction orthogonal to the axial direction of the steering column 3 is defined as the vertical direction, and the horizontal direction orthogonal to the axial direction of the steering column 3 is defined as the horizontal direction.

  As shown in FIGS. 1 and 2, the column cover 16 is made of a synthetic resin having a substantially rectangular tube shape so as to cover the steering column 3, and is attached to the column tube 5 of the steering column 3 at an unillustrated portion. (Hereinafter abbreviated as “instrument panel”) 7 protrudes rearward from the storage opening 10, and the front end side is positioned downward along the axial direction O (see FIG. 2) of the steering column 3, and the rear end side is upward. It is disposed in front of the driver D who is seated at an angle so as to be positioned at the front. As shown in FIGS. 2 and 4, the steering column 3 includes a main shaft 4 and a column tube 5 disposed around the main shaft 4, and a steering wheel 1 is connected to the main shaft 4. . The instrument panel 7 includes an upper panel 8 on the upper side and a lower panel 9 on the lower side.

  Further, as shown in FIGS. 1, 5 and 6, the column cover 16 has a protruding opening 22 when the airbag 50 protrudes in an area extending from the lower surface 18 a side to the left side surface 18 b and the right side surface 18 c of the outer peripheral surface 18. A door portion 24 that is pushed and opened by the airbag 50 is provided. The door portion 24 is disposed on the rear side of the rear surface (lower surface) 12 of the instrument panel 7 (see FIGS. 2 and 4), and includes a lower door portion 25 disposed on the lower surface 18 a side of the column cover 16, and the column cover 16. The left door portion 26 is disposed on the left side surface 18b side, and the right door portion 27 is disposed on the right side surface 18c side of the column cover 16. The periphery is pushed by the inflating airbag 50. A breakable planned portion 23 that can be broken is formed. The planned fracture portion 23 is configured by providing continuous linear concave grooves on the inner peripheral surface side of the peripheral wall portion 17 constituting the column cover 16 so as to reduce the thickness of the column cover 16 (FIG. 5). And the door part 24 will be opened by rotating the front edge 24b side to the back side by using the hinge part 24a which consists of an integral hinge arrange | positioned at the rear edge side of the lower door part 25 as a rotation center at the time of opening. At this time, as shown in FIGS. 3 and 5, the left door portion 26 and the right door portion 27 are connected to the left and right edges of the lower door portion 25 in the state where the lower edge side before opening is respectively connected to the lower door portion 25. At the same time, it opens rearward and is further inverted so as to be in contact with the left side surface 18b and the right side surface 18c of the column cover 16 (see FIG. 6).

  In the case of the embodiment, as shown in FIGS. 1, 5, and 6, the column cover 16 has a door portion on the front side of the door portion 24 so that the area of the protrusion opening 22 of the airbag 50 can be increased. An auxiliary door portion 28 that is pushed together with the air bag 50 together with 24 is provided. The auxiliary door portions 28 are each provided with a planned fracture portion 23 around the auxiliary lower door portion 29 arranged on the lower surface 18a side of the column cover 16 and the auxiliary arranged on the left side surface 18b side of the column cover 16. The left door portion 30 and the auxiliary right door portion 31 disposed on the right side surface 18c side of the column cover 16 are configured. The auxiliary lower door portion 29, the auxiliary left door portion 30, and the auxiliary right door portion 31 are respectively provided with hinge portions 29a, 30a, 31a made of integral hinges on the front edge side, and rear edges 29b, 30b, 31b. It is arrange | positioned so that it may rotate and open to the front side (refer FIG.5, 6).

  As shown in FIGS. 2, 3, and 5, the left and right side walls 17 b of the peripheral wall portion 17 are respectively arranged on the front edge side of the auxiliary door portion 28 and the rear edge side of the door portion 24 inside the column cover 16. Side walls 19 and 20 extending upward from the lower wall 17a of the peripheral wall portion 17 are formed so as to be connected to the right side wall 17c. These side walls 19 and 20 together with the case 43 constitute a storage part P for storing the folded airbag 50. Further, the side walls 19 and 20 serve as a mounting wall for attaching the case 43 that houses the folded airbag 50 and the inflator 34, and the respective locking pieces 45a and 47a of the case 43 are inserted into the peripheral edges. Are provided with a plurality of locking holes 19a, 20a for locking the locking pieces 45a, 47a (see FIGS. 2 and 3).

  In the case of the embodiment, the storage portion P for storing the folded airbag 50 is surrounded by the side walls 45 and 47 in the case 43 on both the front and rear sides, and the left and right sides on the left door portion 26 of the door portion 24 and the right side. Surrounded by the door portion 27, the auxiliary left door portion 30, and the auxiliary right door portion 31, the upper side is surrounded by the ceiling wall 44 of the case 43, and the lower side is the lower door portion 25 and the auxiliary lower door portion 29. (See FIGS. 2 and 3).

  2 to 4, the inflator 34 is connected to the main body 35 having a gas discharge port 36a for discharging the expansion gas, and the outflow direction of the expansion gas discharged from the gas discharge port 36a. And a diffuser 37 that regulates the above. The main body 35 has a substantially cylindrical shape having a cylindrical head portion 36 provided with a plurality of gas discharge ports 36a on the outer peripheral surface at the tip, and in the case of the embodiment, the axial direction is the axis of the steering column 3. The head 36 is arranged along the front-rear direction so as to follow the direction O, and the head 36 is disposed on the rear end side. The diffuser 37 is for flowing the inflation gas G discharged from the gas discharge port 36a toward the left and right sides of the column cover 16, that is, toward the left door portion 26 side and the right door portion 27 side. In the case of the form, it is made of sheet metal and has a substantially rectangular tube shape in which the axial direction is along the left-right direction and both ends are opened. Near the center of the front wall 37a of the diffuser 37 in the left-right direction, an assembly hole 38 having a circular opening for inserting the head 36 side of the main body 35 is formed. Further, two bolts 39 projecting upward are juxtaposed on the ceiling wall 37b of the diffuser 37 along the left-right direction. In the case of the embodiment, the diffuser 37 is housed in a portion between the tethers 57F and 57B in the bag body 51 of the airbag 50, and the airbag 50 and the inflator 34 are attachment holes to be described later of the airbag 50. Each bolt 39 protruded from 55 is protruded from a ceiling wall 44 (described later) of the case 43, and is attached to the case 43 by fixing the nut 40 to a bracket 5a provided on the column tube 5 (FIG. 2). reference). In the embodiment, the knee protection airbag device M is connected to the column tube 5 and connected to the vehicle body side by fastening the bolt 39 to the bracket 5a with the nut 40.

  As shown in FIGS. 2 and 4, the case 43 is made of sheet metal having a substantially inverted U-shaped cross section, and includes a ceiling wall 44 and side walls 45 and 47 extending downward from front and rear edges of the ceiling wall 44. It is configured. The side walls 45 and 47 are inserted into the locking holes 19a and 20a provided in the side walls 19 and 20 of the column cover 16 and connected to the side walls 19 and 20, respectively. 45a and 47a are formed (see FIGS. 2 and 4). The ceiling wall 44 is formed with through holes 44 a through which the bolts 39 of the inflator 34 pass. Further, as shown in FIG. 4, the front side wall 45 of the case 43 is separated in the vicinity of the center in the left-right direction, and the main body 35 of the inflator 34 is fixed to the case 43 at the separated part of the side wall 45. A mounting seat 46 is formed. The mounting seat 46 is arranged with the axial direction substantially along the axial direction O of the steering column 3, that is, the front-rear direction, so as to house the main body 35 with the head 36 side inserted between the side walls 45, 47. It has a substantially half cylindrical shape. Specifically, the mounting seat 46 has a substantially half-cylindrical shape that covers the lower half of the main body 35. A clamp portion 46 a that fixes the main body 35 to the mounting seat 46 is disposed on the front end side of the mounting seat 46. The clamp portion 46 a is configured to fix the main body 35 to the mounting seat 46 by being plastically deformed so as to be pressed against the outer peripheral surface of the main body 35 by reducing the diameter.

  The airbag 50 includes a bag-like bag body 51 that can be inflated by inflating an inflating gas therein, and tethers 57F and 57B disposed in the bag body 51. It is configured as a substantially plate shape.

  When the inflation is completed, the bag body 51 (airbag 50) protrudes from the protruding opening 22 formed by opening the door portion 24 of the column cover 16, and extends substantially in the front-rear direction along the lower surface 18a of the column cover 16. 7 and 8, as shown in FIGS. 7 and 8, a horizontally long rectangular plate having a long left and right side so as to protect the left and right knees K (KL, KR) of the driver D as an occupant. It is configured as a shape. In the case of the embodiment, in detail, the bag body 51 has a substantially trapezoidal shape that is left-right symmetric so that the rear end 51b is wide and the width in the left-right direction is narrowed toward the front edge 51a. When the expansion is completed, the lower side 18a of the column cover 16 and the rear side 12 of the instrument panel 7 from the lower side to the left and right sides of the column cover 16 are covered, and the left and right knees K (KL, KR) is arranged on the vehicle front side. Moreover, the bag main body 51 is arrange | positioned so that it may mutually oppose, as shown in FIGS. 7-9, The passenger | crew side wall part 52 arrange | positioned at the lower surface side used as the driver | operator D side at the time of completion of inflation, And a column side wall portion 53 disposed on the upper surface side which is the column cover 16 side. In the case of the embodiment, the occupant side wall 52 and the column side wall 53 have substantially the same outer shape, and the outer peripheral edges are coupled to each other to constitute the bag body 51.

  As shown in FIG. 7, a circular opening hole 54 is formed in the column side wall 53 near the center of the front, rear, left and right to insert the rear end side (head 36 side) of the main body 35 of the inflator 34. Has been. The insertion hole 54 is formed at a position corresponding to the assembly hole 38 formed in the front wall 37 a of the diffuser 37 when the diffuser 37 of the inflator 34 is accommodated in the airbag 50. Further, attachment holes 55 for projecting the bolts 39 of the diffuser 37 are formed on the left and right sides of the insertion hole 54 in the column side wall 53. In the case of the embodiment, the insertion hole 54 and the attachment hole 55 are formed in a region between the tethers 57F and 57B (a region between the stitched portions 61F and 61B) in the column side wall 53 (see FIGS. 7 and 9).

  The tether 57 is disposed in the bag body 51 so as to connect the occupant side wall portion 52 and the column side wall portion 53. In the case of the embodiment, the bag body 51 is placed on the short side (front-rear direction side). Thus, at two locations that are substantially divided into three positions, they are disposed substantially along the longitudinal direction side (left-right direction side) of the bag body 51 (see FIGS. 7 to 9). Each of the tethers 57 (57F, 57B) is formed in a belt-like shape, and both ends that are spaced apart from each other, specifically, both edges (upper edge 57a and lower edge 57b) on the short side are sewn together. The thread is sewn to the occupant side wall 52 and the column side wall 53, respectively. In the case of the embodiment, each of the tethers 57F and 57B is provided with a gap between both longitudinal edges (the left edge 57c and the right edge 57d) and the lateral edge of the bag body 51. , Both edges (upper edge 57a and lower edge 57b) on the short direction side are respectively used in the width direction (the horizontal direction of the tethers 57F and 57B, which is the longitudinal direction in the illustrated example) using sutures. The occupant side wall 52 and the column side wall 53 are sewn together. In the case of the embodiment, the tether 57B arranged on the rear side is set to have a larger width dimension in the left-right direction than the tether 57F arranged on the front side. In the airbag 50 of the embodiment, the inflator 34 is disposed between the tethers 57F and 57B, and the inflation gas G discharged from the inflator 34 is between the left and right edges of the tethers 57F and 57B and the bag body 51. The bag body 51 flows toward the front edge 51a side and the rear edge 51b side of the bag main body 51 through the gap between them, and the entire bag main body 51 (airbag 50) is inflated (see the two-dot chain line in FIG. 7). .

  Further, in the airbag 50 of the embodiment, the tether 57B arranged at the rear side is stitched with the occupant side wall 52 located on the lower edge 57b side in order to arrange the diffuser 37 of the inflator 34 between the tethers 57F and 57B. The part 60B is configured to be shifted forward from the stitching part 61B with the column side wall 53 located on the upper edge 57a side (see FIG. 9). Further, in the case of the embodiment, as shown in FIGS. 7 and 9, the tether 57B includes a reinforcing portion 58 formed to extend forward from the center in the left-right direction at the upper edge 57a. The reinforcing portion 58 has a substantially rectangular shape, and the periphery of the insertion hole 54 in the column side wall portion 53 and the attachment hole 55 as an attachment portion for attaching the airbag 50 to the case 43 constituting the storage portion P. Are respectively provided with openings corresponding to the insertion holes 54 and the mounting holes 55 (not shown) (see FIG. 10). In the case of the embodiment, the front edge 58a of the reinforcing portion 58 is sewn to the column side wall portion 53 by a stitching portion 61B that sews the upper edge 57a of the tether 57F to the column side wall portion 53.

  In the case of the embodiment, each tether 57F, 57B has a belt-like tether base fabric in which the width dimension (length dimension along the longitudinal direction) is set to be approximately twice the width dimension of each tether 57F, 57B. 69F and 69B (see FIGS. 11 and 12).

  Specifically, as shown in FIG. 12, the tether base fabric 69F constituting the front tether 57F has a belt-like shape whose longitudinal direction extends in the left-right direction, and the tether 57F is a belt-like tether base fabric. The edge portions 69a and 69b on the longitudinal direction side of 69F are configured to be folded and folded along the short-side direction so as to face each other. In the tether 57F, the edges 69a and 69b of the tether base fabric 69F are arranged near the center in the left-right direction. That is, the tether base fabric 69F has a main body 70F configured to have a width dimension in the longitudinal direction coincident with the tether 57F, a right turn portion 72F extending from the right edge of the main body 70F, and a left turn extending from the left edge of the main body 70F. And the right folded portion 72F and the left folded portion 74F are arranged so that the front ends (edge portions 69a and 69b) abut each other on the front side of the main body 70F when mounted on the vehicle. It is said that. In other words, the right folded portion 72F and the left folded portion 74F are configured to overlap the main body 70F on the thickness direction side (front side when mounted on a vehicle) over substantially the entire left and right direction. 57F is configured as a two-layered structure in which the main body 70F, the right folded portion 72F, and the left folded portion 74F are stacked on the thickness direction side over substantially the entire area.

  As shown in FIG. 11, the tether base fabric 69B that constitutes the front tether 57B on the rear side includes a reinforcing portion 71 that constitutes the reinforcing portion 58 in the vicinity of the right edge portion 69b and the central portion in the left-right direction. The tether 57B is formed in a belt shape with the longitudinal direction formed by projecting 73 in the left-right direction, and the tether 57B overlaps the reinforcing portions 71 and 73 with each other while the longitudinal direction side of the tether base fabric 69B. The edge portions 69a and 69b are folded and folded along the short direction so as to abut each other. In FIG. 11, since the tether base fabric 69B and the tether 57B are viewed from the upper side with the front side when the vehicle is mounted as the lower side, the left and right are reversed from those when the vehicle is actually mounted. In the tether 57B, the edges 69a and 69b of the tether base fabric 69B are arranged at positions shifted leftward from the left and right centers on the left side of the reinforcing portion 58. That is, the tether base fabric 69B is configured to have a width dimension in the longitudinal direction that coincides with that of the tether 57B, and is provided with a main body 70B having a reinforcing portion 71 (the center in the left-right direction of the tether 57B is symmetrical). ), A right turn portion 72B (which is asymmetrical with respect to the center in the left-right direction of the tether 57B) extending from the right edge of the main body 70B and a left turn extending from the left edge of the main body 70B. Portion 74B (which is asymmetrical with respect to the center of the tether 57B in the left-right direction), and the right turn-back portion 72B and the left turn-back portion 74B are arranged on the rear surface side of the main body 70B when mounted on the vehicle. It is set as the structure arrange | positioned so that it may mutually face. In other words, the right folded portion 72B and the left folded portion 74B are configured to overlap the main body 70B on the thickness direction side (rear surface side when mounted on the vehicle) over substantially the entire left and right direction. 57B is configured as a two-layered structure in which the main body 70B, the right folded portion 72B, and the left folded portion 74B are stacked on the thickness direction side over substantially the entire area. Further, the reinforcing portion 58 of the tether 57B is also configured as a two-layer structure in which a reinforcing portion 71 extending from the main body 70B and a reinforcing portion 73 extending only from the right folded portion 72B are stacked on the thickness direction side. ing.

  In the case of the embodiment, each of the tethers 57F and 57B has a main body 70F in the tether 57F disposed in front of the diffuser 37 so that the edges 69a and 69b of the tether base fabrics 69F and 69B are not disposed on the inflator 34 side. The tether 57B disposed behind the diffuser 37 is disposed in the bag body 51 so that the body 70B is positioned forward. That is, in the airbag 50 of the embodiment, the tether 57F, 57B is discharged from the inflator 34 to the longitudinal end of the tether base fabric 69F, 69B (longitudinal side edges 69a, 69b). Since the expansion gas G does not hit, the edges 69a and 69b can be prevented from being damaged by the expansion gas G, and the tensile strength of the tethers 57F and 57B can be accurately prevented from being lowered.

  The bag body 51 is configured by sewing (bonding) the peripheral edges of a base fabric having a predetermined shape. In the case of the embodiment, as shown in FIG. 63, an occupant-side front panel cloth 66 that constitutes a front side region of the region obtained by dividing the region of the occupant side wall portion 52 in the short side (front-rear direction) side, and an occupant that constitutes a central region of the occupant side wall portion 52 The side center panel cloth 67 is comprised. The column side panel cloth 63 has a shape in which a column side portion 64 that constitutes the entire region of the column side wall portion 53 and a rear lower side portion 65 that constitutes a rear region of the occupant side wall portion 52 are connected in series. Has been. The occupant-side front panel cloth 66 and the occupant-side central panel cloth 67 are formed in a substantially strip shape whose longitudinal direction is substantially along the left-right direction.

  In the airbag 50 of the embodiment, the lower edges 57b of the tethers 57F and 57B are the occupant-side front panel cloth 66, the occupant-side center panel cloth 67, and the rear lower part that constitute the occupant side wall 52 in the bag body 51. When the corresponding edges of the side portions 65 are sewn, they are sewn together and sewn to the occupant side wall 52. Specifically, the lower edge 57 b of the tether 57 F is sewn together when the rear edge 66 a of the occupant side front panel cloth 66 and the front edge 67 a of the occupant side center panel cloth 67 are sewn. In other words, the stitched portion 60F in which the lower edge 57b of the tether 57F is sewn to the occupant side wall portion 52 has an occupant side wall portion 52 (the occupant side front panel cloth 66 or the occupant side center panel cloth 67 over substantially the entire length direction). ), The main body 70F of the tether base fabric 69F, the right folded portion 72F, the left folded portion 74F, and the occupant side front panel fabric 66 or the occupant side front panel fabric 66 are stacked on the thickness direction side. It is disposed in the region of the three-layer structure. The lower edge 57b of the tether 57B is sewn together when sewing the rear edge 67b of the occupant-side center panel cloth 67 and the front edge 65a of the rear lower side portion 65. In other words, the stitched portion 60B in which the lower edge 57b of the tether 57B is sewn to the occupant side wall 52 is the occupant side wall 52 (the occupant side central panel cloth 67 or the rear lower side 65) over substantially the entire length direction. In contrast, the main body 70B of the tether base fabric 69B, the right folded portion 72B, the left folded portion 74B, and the occupant side central panel fabric 67 or the rear lower side portion 65 are stacked in the thickness direction side. It is disposed in the region of the overlapping structure.

  In the airbag 50 of the embodiment, the upper edge 57a of each tether 57F, 57B is sewn to the column side portion 64 of the column side panel cloth 63. That is, the stitched portion 61B in which the upper edge 57a of the tether 57B is sewn to the column side wall portion 53 has a main body 70B, a right folded portion 72B, and a left folded portion with respect to the column side portion 64. 74B is disposed in a two-layered region in which the layers 74B are stacked on the thickness direction side. Further, the upper edge 57a of the tether 57F is sewn to the column side wall 53 together with the front edge 58a of the reinforcing portion 58 extending from the tether 57B in the vicinity of the central portion in the left-right direction. That is, the stitching portion 61F in which the upper edge 57a of the tether 57F is sewn to the column side wall portion 53 is in the vicinity of both ends in the left-right direction, with respect to the column side portion 64, the main body 70F in the tether base fabric 69F, The folded portion 72F, the left folded portion 74F, and the reinforcing portions 71 and 73 in the tether base fabric 69B are disposed in a four-layered region in which they are stacked in the thickness direction. The main body 70F of the tether base fabric 69F, the right folded portion 72F, and the left folded portion 74F are disposed in a two-ply region overlapping the side portion 64 in the thickness direction.

  In the airbag 50 of the embodiment, the lower edge 57b of each tether 57F, 57B is between the occupant-side front panel cloth 66 and the occupant-side central panel cloth 67, or between the occupant-side central panel cloth 67 and the rear lower side, respectively. It arrange | positions between the parts 65, and it is comprised so that it may expose a little on the passenger | crew side wall part 52 surface (refer FIG. 8, 9). In the airbag 50 according to the embodiment, the column side panel cloth 63, the occupant side front panel cloth 66, the occupant side center panel cloth 67, and the tether base cloth 69F that configure the tethers 57F and 57B are included. 69B is formed from a woven fabric made of flexible polyester, polyamide yarn or the like.

  Next, manufacture of the airbag 50 of embodiment is demonstrated. An insertion hole 54 and a mounting hole 55 are formed in advance in the tether base cloth 69B and the column side panel cloth 63. Further, the tether base fabrics 69F and 69B are folded at predetermined positions to form the tethers 57F and 57B in advance. First, the occupant-side front panel cloth 66 and the occupant-side center panel cloth 67 are overlapped so that the rear edge 66a and the front edge 67a coincide with each other with the lower edge 57b of the tether 57F interposed therebetween, and the rear edge 66a , The front edges 67a are sewn together with the lower edge 57b of the tether 57F to form a stitched portion 60F. Next, the rear edge 67b and the front edge 65a are made to coincide with each other with the passenger side center panel cloth 67 and the rear lower side portion 65 of the column side panel cloth 63 sandwiched between the lower edges 57b of the tether 57B. Overlap, the rear edge 67b and the front edge 65a are sewn together with the lower edge 57b of the tether 57B to form the stitched portion 60B and the occupant side wall 52. Thereafter, the upper edge 57a of the tether 57B is sewn to the column side portion 64 of the column side panel cloth 63 to form a stitched portion 61B. Then, the tether 57F is overlaid on the column side part 64 so that the upper edge 57a and the front edge 58a of the reinforcing part 58 extending from the tether 57B coincide with each other, and the upper edge 60a together with the front edge 58a of the reinforcing part 58 is columned. The side portion 64 is sewn to form a suture site 61F. If the occupant side wall portion 52 and the column side wall portion 53 are overlapped so that the outer peripheral edges coincide with each other, the outer peripheral edges are sewn together, whereby the airbag 50 can be manufactured.

  Then, after the airbag 50 is manufactured, the airbag 50 is folded. Specifically, in a state in which the diffuser 37 is accommodated in the interior so that the bolt 39 protrudes from the mounting hole 55, the occupant side wall portion 52 and the column side wall portion 53 are flattened, and the width of the front, rear, left, and right. The airbag 50 is folded so that the dimensions are reduced. Thereafter, the folded airbag 50 is wrapped around with a wrapping material (not shown) for preventing collapse so as not to collapse. At this time, the bolt 39 is protruded from the wrapping material. Next, the folded airbag 50 is housed in a portion of the case 43 between the side walls 45 and 47 while the bolt 39 of the diffuser 37 is projected from the ceiling wall 44. Then, the main body 35 of the inflator 34 is disposed on the upper surface side of the mounting seat 46, the head portion 36 side is inserted into the insertion hole 54 of the airbag 50, and the clamp portion 46a is plastically deformed to reduce the diameter, The inflator 34 is formed by assembling the main body 35 to the diffuser 37. At this time, the inflator 34 can be connected to the airbag 50 and can be fixed to the case 43 so that the airbag assembly can be assembled.

  The airbag assembly assembled in this manner is fastened to the bracket 5a provided on the column tube 5 of the steering column 3 by fastening each bolt 39 with the nut 40, and extends from the airbag operating circuit (not shown). If the lead wire is connected to the main body 35 of the inflator 34 and the column cover 16 is attached to the steering column 3, the knee protecting airbag device M can be mounted on the vehicle.

  In the airbag apparatus M for knee protection of the embodiment, if an operation signal is input to the main body 35 of the inflator 34 through a lead wire (not shown) after being mounted on the vehicle, the gas discharge port 36a provided in the main body 35 is used. The expansion gas G is discharged. Then, the inflation gas G flows into the airbag 50 through the openings 37c and 37d on the left and right ends of the diffuser 37. Thereafter, the inflating airbag 50 protrudes downward from a protruding opening 22 formed by pushing open the door portion 24 and the auxiliary door portion 28 formed in the column cover 16, and is indicated by a two-dot chain line in FIGS. And as shown in FIG. 13, expansion | swelling will be completed.

  And in the airbag 50 used for the knee protection airbag apparatus M of embodiment, in the tether 57F (57B), the stitching | suture site | parts 60F and 61F (60B) with the passenger | crew side wall part 52 and the column side wall part 53 of the bag main body 51. , 61B) are disposed over the entire area in the length direction with respect to the main body 70F (70B) of the tether base fabric 69F (69B), the right folded portion 72F (72B) and the left folded portion 74F (74B). ) On the thickness direction side. In other words, the tether 57F (57B) is a portion where at least three of the tethers 57F (57B) including the occupant side wall 52 and the column side wall 53 of the bag main body 51 overlap and are sewn to the occupant side wall 52 and the column side wall 53 of the bag main body 51. It is worn.

  Specifically, in the airbag 50 of the embodiment, the stitched portion 61F that sews the upper edge 57a of the tether 57F to the column side wall 53 has the reinforcing portion 58 extending from the tether 57B in the vicinity of the center in the left-right direction. Sewing. Therefore, the stitching part 61F is arranged in a five-layered region including the column side wall 53 near the center in the left-right direction, and includes the column side wall 53 in the region on both sides in the left-right direction where the reinforcing part 58 is not arranged. It is arranged in a three-ply area. A stitching portion 61B for sewing the upper edge 57a of the tether 57B to the column side wall 53 is disposed in a three-layer region including the column side wall 53. Further, the stitched portions 60F and 60B for sewing the lower edges 57b of the tethers 57F and 57B to the occupant side wall 52 are respectively the occupant side front panel cloth 66, the occupant side center panel cloth 67, and the occupant side wall part 52. Since it is formed by sewing together with the rear lower side portion 65, it is arranged in a four-layered region over substantially the entire length direction. Therefore, in the airbag 50 of the embodiment, the stitching strength of the stitched portions 60F, 60B, 61F, 61B in which the tethers 57F, 57B are sewn to the passenger side wall 52 and the column side wall 53 can be increased. Since the tensile strength of the tethers 57F and 57B can be increased, the stitched portions 60F, 60B and 61F of the tethers 57F and 57B with the occupant side wall 52 and the column side wall 53 are used even when using an inflator with a large output. , 61B, even if stress concentration occurs, the load on the tethers 57F, 57B can be reduced (dispersed). Further, in the airbag 50 of the embodiment, the tethers 57F and 57B are formed by folding the tether base fabrics 69F and 69B on the both edges (left edge 57c and right edge 57d) on the longitudinal direction side. It is set as the structure which has the part 72F, 72B or the left folding | returning part 74F, 74B. That is, in the airbag 50 of the embodiment, the ends (longitudinal side edges 69a and 69b) of the tether base fabrics 69F and 69B are connected to both longitudinal side edges (the left edge 57c and the right edge) of the tethers 57F and 57B. 57d side), when the airbag 50 is inflated, the tether base fabrics 69F and 69B can be prevented from fraying from the terminal (edge portions 69a and 69b) side, and the bag body 51 can be stably inflated. Can be made.

  Therefore, in the airbag 50 of the embodiment, the tensile strength of the tethers 57F and 57B can be improved, and the inflated completed shape of the bag body 51 can be stabilized.

  Further, in the airbag 50 of the embodiment, the tethers 57F and 57B are overlapped with the main bodies 70F and 70B and the folded portions (right folded portions 72F and 72B or left folded portions 74F and 74B) on the thickness direction side over substantially the entire area. Further, since the two sheets are stacked, the tensile strength of the tethers 57F and 57B can be further improved. Of course, if such a point is not taken into consideration, the folded portion formed in the vicinity of both edges on the direction side along the suture site is arranged so as to extend only in the vicinity of the site where the suture site is arranged. It is also possible to use a configuration in which the folded portion is not disposed at an intermediate portion that is located between the suture sites in the tether and that is remote from the suture site.

  Furthermore, in the airbag 50 of the embodiment, the tether 57B is configured to include the reinforcing portion 58 that can reinforce the peripheral edge of the mounting portion (mounting hole 55) that attaches the airbag 50 to the case 43 constituting the storage portion P. The reinforcing portion 58 has a two-layer structure in which a reinforcing portion 71 extending from the main body 70B and a reinforcing portion 74 extending only from the right folded portion 73B are stacked on the thickness direction side. Therefore, in the airbag 50 of the embodiment, it is not necessary to arrange a separate reinforcing cloth around the periphery of the attachment hole 55. Further, the reinforcing portion 58 is formed as a reinforcing portion 71 extending from the main body 70B and the reinforcing portion 74 extending only from the right folded portion 73B, which occupy the entire reinforcing area without being divided. Since the reinforcing portions 71 and 74 are overlapped on the thickness direction side, a sufficient tensile strength can be secured even at the periphery of the attachment portion (attachment hole 55). Of course, if such a point is not taken into consideration, the reinforcing portion may not be provided on the tether, and a reinforcing cloth may be provided separately.

  In the embodiment, each of the tethers 57F and 57B is configured such that the edges 69a and 69b abut each other in the tether base fabrics 69F and 69B. The case where the gap is formed to have a slight gap is also considered. However, the tethers 57F and 57B have the main bodies 70F and 70B over substantially the entire region even if a slight gap is formed between the edges 69a and 69b (between the right folded portions 72F and 72B and the left folded portions 74F and 74B). And the folded portion (right folded portions 72F and 72B or left folded portions 74F and 74B) are stacked on the thickness direction side, the tensile strength can be ensured. Of course, the tether may be configured such that the edges overlap each other. In this case, the overlapping region may be large as long as it does not interfere with the suturing operation.

  Further, in the knee protection airbag device M of the embodiment, since the inflator 34 is disposed between the tethers 57F and 57B in the airbag 50, the distance from the inflator 34 to the tethers 57F and 57B is short, and the inflator 34 The inflation gas discharged from the air flows through the gap between the tethers 57F and 57B and the left and right edges of the bag body 51 in the initial stage of inflation of the airbag 50. The tethers 57F and 57B have a tensile strength. The bag body 51 can be quickly and stably inflated without being damaged by the inflating gas since it is improved and firmly sewn to the passenger side wall 52 and the column side wall 53.

  In the embodiment, an airbag having a configuration in which an inflator is disposed between tethers and used in a knee protection airbag device with a steering column is described as an example. However, an airbag to which the present invention can be applied is described. However, the present invention is not limited to this, and the present invention may be applied to an airbag of a knee protection airbag device or an airbag of a side impact airbag device disposed below the steering column or below the grab box in front of the passenger seat. The invention may be applied.

1 is a schematic side view of the vicinity of a column cover on which a knee protecting airbag device using an airbag according to an embodiment of the present invention is mounted. It is a general | schematic expanded longitudinal cross-sectional view along the front-back direction of the column cover vicinity in which the airbag apparatus for knee protection of embodiment is mounted. It is a general | schematic expanded cross-sectional view of the column cover vicinity in which the airbag apparatus for knee protection of embodiment is mounted, and respond | corresponds to the III-III site | part of FIG. It is a disassembled perspective view of the case and inflator which are used for the airbag apparatus for knee protection of embodiment. It is a top view of the lower part of the column cover by which the airbag apparatus for knee protection of embodiment is mounted. It is a perspective view which shows the state before the door part opens in the column cover in which the airbag apparatus for knee protection of embodiment is mounted, and the open state. It is a top view of the airbag used for the airbag apparatus for knee protection of embodiment. It is a bottom view of the airbag of FIG. It is a longitudinal cross-sectional view of the airbag of FIG. 7, and respond | corresponds to the IX-IX site | part of FIG. It is a top view which shows the base fabric which comprises the airbag of FIG. It is a figure which shows one tether used for the airbag of FIG. 7, and is a top view of the tether base fabric and the tether formed by folding the tether base fabric. It is a figure which shows the other tether used for the airbag of FIG. 7, and is a top view of the tether base fabric and the tether formed by folding the tether base fabric. FIG. 4 is a schematic enlarged longitudinal sectional view along the front-rear direction showing a state where the airbag is inflated when it is placed in the knee protection airbag device of the embodiment.

Explanation of symbols

16 ... Column cover,
34 ... Inflator,
43 ... Case,
50 ... Airbag,
51 ... Bag body,
52 ... Passenger side wall,
53. Column side wall,
55 ... Mounting hole (mounting part),
57F, 57B ... tether,
58 ... reinforcement part,
60F, 60B, 61F, 61B ... suture site,
69F, 69B ... Tether base fabric,
70F, 70B ... main body,
71, 73 ... reinforcing parts,
72F, 72B ... right turn part,
74F, 74B ... Left folded part,
D ... Driver (occupant),
K (KL, KR) ... knees,
M: Air bag device for knee protection.

Claims (3)

A bag-shaped bag body that can be inflated by allowing inflation gas to flow therein; and a tether that is disposed in the bag body and that connects the wall portions of the bag body that are opposed to each other. Then, the expansion completion shape is configured as a substantially plate shape,
The tethers are substantially band-shaped, and both ends of the tethers that are spaced apart from each other are sewn to the respective wall portions along the width direction using sutures, thereby connecting the wall portions to each other. An airbag having a configuration,
The tether is configured to have a folded portion formed by folding a tether base fabric on both edge sides of the direction side along the stitched portion with the wall portion,
The folded portion is at least on the side in the thickness direction over substantially the entire length of the stitched portion with respect to the main body of the tethered base fabric at a portion where the stitched portion between the tether and the wall portion is disposed. An airbag characterized in that the airbag is configured to be overlaid with the air bag.   2. The airbag according to claim 1, wherein the tether has a two-layer structure in which the main body and the folded portion are overlapped on a thickness direction side over substantially the entire region. The tether is configured to include a reinforcing portion that can reinforce a peripheral edge of an attachment portion that attaches the airbag to a storage site.
The said reinforcement part is made into the 2 sheet | seat overlapping structure on which the member extended from the said main body and the member extended only from one said said folding | returning part were piled up on the thickness direction side. Airbag.

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