Vehicle seat

Abstract

To form a burst part of a seat cover as a projecting portion of an air bag with two intersecting sewing lines while appropriately ensuring its cleavage performance.SOLUTION: A vehicle seat is so structured that a burst part 20 formed at sewn portions of a seat cover 10 is released and thereby an air bag jumps out to a seat sitting side. A first sewn line 21 extending in a seat vertical direction and a second sewn line 22 extending in a direction intersecting with the first sewn line 21 cross with each other in the burst part 20. Webbing (either of a first webbing 51 to a fourth webbing 54) regulating elongation in a direction of the surface of the seat cover when the air bag jumps out is provided to each of a plurality of sections, when the part of the seat cover 10 around the burst part 20 is divided to a plurality of sections (a first section 31 to a fourth section 34) by the first sewn line 21 and the second sewn line 22.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a vehicle seat having a seat cover forming the outer surface of the seat and an airbag held on the seat inner side of the seat cover. [Background technology]

[0002] Patent Document 1 discloses technology related to this type of vehicle seat. The vehicle seat of Patent Document 1 has a seat back, which serves as a backrest, attached to the rear of a seat cushion, which serves as a seating portion. The seat back also has a seat cover that defines its outer shape and a pad covered by the seat cover. An airbag device is disposed on the side (left side) of the seat back in the width direction of the seat. This airbag device is held by the back side of the pad and is disposed on the seat inner side of the seat cover that forms the outer surface of the seat. In the event of a vehicle collision, an airbag inflates from the airbag device, tears open the seams of the seat cover, and is ejected toward the seat occupant.

[0003] The above-described seat cover has a cross-shaped seam where the airbag will protrude. Specifically, the seat cover has vertical seams extending above and below the seat between the seat cover (the cover portion on the seating surface side) and the cover portion on the right cover portion side. The horizontal seams on the cover portion extend in the seat front-rear direction, cross-intersecting the vertical seams. The back side of the cover portion has strip-shaped webbings extending above and below the horizontal seams in the seat front-rear direction. In this configuration, the upper and lower webbings suppress the stretching of the seat cover when the airbag protrudes, thereby promoting the tearing of the vertical seams. Furthermore, the inflation pressure of the airbag tears the horizontal seams, allowing the airbag to protrude toward the seat from the cross-shaped tearing seams. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2002-2344 Summary of the Invention [Problem to be solved by the invention]

[0005] The above-mentioned technology provides a cross-shaped seam (burst portion) and then uses a webbing to suppress the stretch of the seat cover and promote tearing of the vertical seam (first seam line). However, if webbing is provided only on the seat cover covering portion (right seat cover surface), it is not possible to control the stretch of the cover portion on the seating surface side, which can make it difficult to ensure appropriate tearing properties of the vertical seam, such as the tearing range and tearing speed. Furthermore, in the above-mentioned configuration, it is desirable to also be able to control the tearing properties of the horizontal seam (second seam line) from the perspective of more appropriately ensuring the tearing properties of the vertical seam. The present invention was devised in light of the above-mentioned points, and the problem to be solved by the present invention is to form the burst portion of the seat cover, which is the point at which the airbag will protrude, with two intersecting seam lines while more appropriately ensuring its tearing properties. [Means for solving the problem]

[0006] As a means for solving the above problems, a vehicle seat according to a first aspect of the present invention has a seat back that serves as a backrest, which includes a seat cover forming the outer surface of the seat and an airbag held inside the seat cover. The airbag is configured to burst toward the seat occupant's side when a burst portion formed at a seam in the seat cover is released. The burst portion of the present invention intersects a first seam line extending in the seat's vertical direction with a second seam line extending in a direction intersecting the first seam line. In this type of seat configuration, it is desirable to form the burst portion of the seat cover, which is the portion where the airbag will burst, with two intersecting seam lines while more appropriately ensuring its tearability. Therefore, in this invention, when the seat cover portion around the burst portion is divided into multiple sections by the first seam line and the second seam line, a webbing is provided in each section to restrict the stretch of the seat cover in the planar direction when the airbag bursts. In the present invention, the seat cover portion around the burst part is divided into multiple sections by a first seam line and a second seam line, and webbing is provided in all of the multiple sections. This makes it possible to control the stretch of the seat cover portion around the burst part for each section, and makes it possible to more reliably rip open the appropriate places of each seam line.

[0007] The vehicle seat of the second invention is the vehicle seat of the first invention, wherein the seat cover portion around the burst portion is formed with at least one region: a first extensible region in which extensibility propagates in the plane direction within one section, and a second extensible region in which extensibility propagates in the plane direction across two sections divided above and below by a second seam line. The first extensible region is provided with at least one restraining portion that suppresses extensibility of the seat cover, and a webbing provided in one section is arranged so as to span between the first seam line and the restraining portion. The second extensible region is provided with another restraining portion that suppresses extensibility of the seat cover, and the webbings arranged in the two sections are connected via a second seam line so as to span between the first seam line and the other restraining portion. This invention allows the webbing of each section to be more appropriately positioned depending on the type of extensible region formed in the seat cover portion around the burst portion.

[0008] The vehicle seat of the third invention is the vehicle seat of the second invention, in which a linearly formed restraining portion is provided in the first extensible region along the second seam line. In this invention, the webbing arranged in the first extensible region can be stretched between the first seam line and the restraining portion on the second seam line.

[0009] The vehicle seat of the fourth invention is the vehicle seat of any one of the first to third inventions, in which the second seam line is provided with a reinforcing portion that reinforces the second seam line to prevent it from opening. In this invention, the reinforcing portion functions to control the tearability of the second seam line, for example, by limiting the tear range, making it possible to more appropriately ensure the tearability of the first seam line. [Effects of the Invention]

[0010] According to the first aspect of the present invention, the burst portion of the seat cover, which is the portion from which the airbag will protrude, can be formed with two intersecting stitching lines while more appropriately ensuring its tearability. According to the second aspect of the present invention, the tearability of the burst portion can be ensured while taking into account the stretch of the seat cover around it. According to the third aspect of the present invention, the tearability of the burst portion can be even more appropriately ensured. And according to the fourth aspect of the present invention, the tearability of the burst portion can be even more appropriately ensured. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a schematic perspective view of a vehicle seat. [Figure 2] 1 is a schematic perspective view of a vehicle seat showing a seat pad; [Figure 3] FIG. 10 is a schematic side view of the seat back showing the seat cover around the burst portion. [Figure 4] FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. 3. [Figure 5] FIG. 4 is a cross-sectional view taken along line VV in FIG. [Figure 6] FIG. 6 is a cross-sectional view taken along line VI-VI in FIG. [Figure 7] FIG. 7 is a cross-sectional view taken along line VII-VII in FIG. 3. [Figure 8] FIG. 10 is a schematic perspective side view of the seat back showing the webbing around the burst portion. [Figure 9] FIG. 9 is a cross-sectional view taken along line IX-IX in FIG. [Figure 10] FIG. 4 is a cross-sectional view taken along line XX in FIG. 3. [Figure 11] FIG. 2 is a schematic perspective view of a seat back showing each stretchable region. [Figure 12] FIG. 2 is a schematic perspective view of a seat back when an airbag is ejected. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, an embodiment of the present invention will be described with reference to Figures 1 to 12. In each figure, arrows indicating the front-rear direction, the up-down direction, and the left-right direction (seat width direction) of the vehicle seat are appropriately shown. For convenience, Figure 2 partially illustrates grooves provided in the seat pad.

[0013] [Vehicle seat overview] First, an overview of a vehicle seat 2 shown in Fig. 1 will be described. In this vehicle seat 2, the lower part of a seat back 6 is connected via a recliner (not shown) to the rear part of a seat cushion 4, which serves as a seating portion. This seat back 6 is a member against which the occupant rests, and is formed in a vertically long rectangular shape when viewed from the front. Referring to Figs. 1 and 2, in the seat back 6, a seat cover 10, which forms the outer surface of the seat, covers a metal seat frame 6F that forms the seat skeleton, and a foam resin seat pad 6P that elastically supports the occupant.

[0014] Here, a seating surface 6A on which an occupant can sit is formed in the center of the front of the seat back 6 shown in Figure 1, extending in the vertical direction of the seat. The seat back 6 also has bank portions 6B that bulge toward the seating side on both sides (right and left sides) of the seating surface 6A in the seat width direction (for convenience, only the bank portion on the right side is designated by a corresponding symbol in Figure 1). The inside portion of the bank portion 6B (the left side portion of the right bank portion 6B) forms a top panel side portion 6C of the seat back 6. The outside portion of the bank portion 6B (the right side portion of the right bank portion 6B) forms a right flank surface 6D of the seat back 6.

[0015] An airbag device 7 is installed inside the seat back 6 shown in Fig. 1, on the upper right side thereof. The airbag device 7 houses an uninflated airbag 8 and an inflator (gas supply device, gas generating agent, etc.) that inflates the airbag 8. Referring to Figs. 1 and 2, the airbag device 7 is held by the seat frame 6F and is disposed inside the seat of the seat cover 10. In the above-described configuration, the airbag 8 inflates from the airbag device 7 in the event of a vehicle collision, that is, is ejected while inflating. The inflated airbag 8 then bursts out toward the seat occupant's seat when the stitching of the seat cover 10 (burst portion 20, described later) is released.

[0016] 1 and 3, a burst portion 20 is formed in a cross shape on the right side of the seat cover 10 as a stitched portion that serves as a protrusion location for the airbag 8. That is, a first stitching line 21 is formed on the right side of the seat cover 10 on the side of the right flank surface 6D as a stitched portion that extends vertically from the seat. A second stitching line 22, another stitching portion, crosses the first stitching line 21 on the upper part of the seat cover 10. In the above-described configuration, in order to ensure proper protrusion of the airbag 8 shown in FIG. 1, it is desirable to ensure the tearability of the burst portion 20, particularly the tearability of the first stitching line 21. Therefore, in this embodiment, the burst portion 20 of the seat cover 10 is formed with two intersecting stitching lines while more appropriately ensuring its tearability by using the configuration (restraint portion, webbing, reinforcing portion, and stretch region) described below and shown in FIGS. 3 and 11. The configuration of the seat cover 10 will be described in detail below in the order of the burst portion 20, the restraining portions (40-42), the webbing (51-54), the reinforcing portion 60, and the stretchable regions (71A, 71B, 72).

[0017] [Burst section] First, the cross-shaped burst portion 20 shown in FIGS. 1 and 3 is formed by the intersection of the first seam line 21 and the second seam line 22, as described above. The first seam line 21 extends vertically on the right flank surface 6D, extending from the top to the bottom of the right flank surface 6D. The second seam line 22 is formed so as to straddle the right flank surface 6D and the top panel side portion 6C. The second seam line 22 extends in a direction intersecting with the first seam line 21 in the surface direction of the seat cover 10, i.e., extends generally in the seat front-rear direction on the right flank surface 6D side shown in FIG. 3 and in the seat width direction on the top panel side portion 6C side. The first seam line 21 and the second seam line 22 intersect at the upper position of the right portion of the seat cover 10, thereby forming the cross-shaped burst portion 20. The burst portion 20 is formed in the upper portion of the seat back 6 shown in FIG.

[0018] [How to divide the seat cover around the burst area (division method)] The seat cover 10 portion around the burst portion 20 shown in Fig. 3 (hereinafter referred to as the seat cover 10 portion) can be divided into a plurality of sections (first section 31 to fourth section 34) by a first seam line 21 and a second seam line 22. That is, the seat cover 10 portion described above is divided into a front side and a rear side by the first seam line 21, and further divided into an upper side and a lower side by the second seam line 22. Each of the first section 31 to fourth section 34 has one cover region (any of the first cover region 11 to fourth cover region 14) that forms the seat cover 10 portion disposed therein.

[0019] Here, the first cover region 11 to the fourth cover region 14 shown in Fig. 3 can be formed of, for example, fabric (woven fabric, knitted fabric, nonwoven fabric) or leather (natural leather, artificial leather). A padding material such as urethane laminate or a backing fabric (not shown) is disposed on the back side of each cover region. In the seat cover 10 portion described above, adjacent cover regions are sewn together by first seam lines 21 and second seam lines 22 (see institches 20S shown in Fig. 4, etc.). At the intersection 20X of the first seam line 21 and the second seam line 22 (and its surroundings), the seam allowances of the four cover regions are sewn together, making the intersection thicker than the other seam regions.

[0020] [Each section] In the above-described configuration, a first section 31 in which the first cover portion 11 is disposed is provided on the upper front side of the seat cover 10 portion shown in FIG. 3 . This first section 31 is separated and compartmented from the rest of the seat cover 10 portion by being surrounded by an upper portion (210) of the first seam line and a front portion (220) of the second seam line. A second section 32 in which the second cover portion 12 is disposed is provided on the lower front side of the seat cover 10 portion. This second cover portion 12 is surrounded by a lower portion (211) of the first seam line and a front portion (220) of the second seam line. A third section 33 in which the third cover portion 13 is disposed is provided on the upper rear side of the seat cover 10 portion, and this third section 33 is surrounded by an upper portion (210) of the first seam line and a rear portion (221) of the second seam line. A fourth section 34 in which the fourth cover portion 14 is arranged is provided at the lower rear side of the seat cover 10 portion, and this fourth section 34 is surrounded by the lower part (211) of the first seam line and the rear part (221) of the second seam line.

[0021] [Suppression site] The seat cover 10 shown in Fig. 3 is provided with multiple restraining portions (lateral restraining portions 40, front vertical restraining portions 41, and rear vertical restraining portions 42) that restrain its elongation. Referring to Figs. 3 and 5, the lateral restraining portions 40 are formed by engaging resin lateral suspender portions 40A fixed to the seat cover 10 with the seat pad 6P. The lateral suspender portions 40A are formed from a substantially rectangular resin plate, and are sewn together with the seams of the first cover portion 11 and the second cover portion 12 with their thickness directions facing up and down. The lateral suspender portions 40A are linearly arranged along the front portion (220) of the second seam line, and the arrowhead-shaped tip portions 400 of the lateral suspender portions 40A face the seat pad side.

[0022] 2 and 5, a horizontal groove 40B is provided at the upper portion of the seat pad 6P along the second seam line 22. A plate-shaped horizontal locking portion 40C is fixed in front of the horizontal groove 40B, i.e., at a position corresponding to the front portion 220 of the second seam line. A pair of locking claws 401 protrudes from the surface of the horizontal locking portion 40C. When the seat pad 6P is covered with the seat cover 10 shown in FIG. 5, the tip end 400 of the horizontal suspender portion 40A is locked to the locking claws 401 of the horizontal locking portion 40C. As a result, the seat cover 10 shown in FIG. 3 is provided with a linear horizontal restraining portion 40 that restricts elongation along the front portion (220) of the second seam line. The horizontal restraining portion 40 is positioned slightly forward of the intersection 20X (thick portion) of the seam lines and extends from the right gusset surface 6D toward the top panel side portion 6C.

[0023] The front vertical restraining portion 41 shown in FIG. 3 is formed by fastening a vertical suspender portion 41A fixed to the seat cover 10 to the seat pad side. The vertical suspender portion 41A is sewn together with the left edge (front side) of the second cover portion 12 shown in FIG. 6 at the seam between the left edge (front side) of the second cover portion 12 and the seating surface side cover portion 15, thereby extending in the seat up-down direction. Referring to FIGS. 2 and 6, the seat pad 6P is formed with a vertical groove portion 41B extending in the seat up-down direction along the left edge (front side) of the second cover portion 12. When the seat pad 6P is covered with the seat cover 10, the vertical suspender portion 41A is fastened to a vertical fastening portion 41C in the vertical groove portion 41B. In this way, the seat cover 10 is provided with the front vertical restraining portion 41 that restricts the stretch of the seat cover 10, extending in the seat up-down direction along the left edge (front side) of the second cover portion 12.

[0024] The rear vertical restraining portion 42 shown in Figure 3 is formed with a linear fastener structure and is provided between the rear edge of the fourth cover portion 14 and the rear cover portion. That is, referring to Figures 3 and 7, the rear vertical restraining portion 42 is formed by the engagement of a first fastener 42A fixed to the fourth cover portion 14 and a second fastener 42B fixed to the rear cover portion 16. The portions of the first fastener 42A and the second fastener 42B that are sewn to the corresponding cover portions are made of resin. Thus, the rear vertical restraining portion 42 that restricts elongation of the seat cover 10 is provided so as to extend in the seat up-down direction along the rear edge of the fourth cover portion 14.

[0025] [Rikifu] Next, the seat cover 10 portion shown in FIGS. 3 and 8 is provided with multiple webbing (first webbing 51 to fourth webbing 54). Each webbing is a member that restricts the stretch of the seat cover 10 in the surface direction and is disposed on the back side of the seat cover 10. The material of each webbing is not particularly limited, but it is preferable that it has a rigidity sufficient to withstand the pressure when the airbag inflates, and it is typically formed of a face material such as fabric that is less stretchable than the seat cover 10. Then, in the seat cover 10 portion, as will be described later, a webbing (one of the first webbing 51 to fourth webbing 54) is disposed in each of the first to fourth sections 31 to 34. That is, the first webbing 51 to fourth webbing 54 are disposed so as to fit within the corresponding section without straddling the first seam line 21 and the second seam line 22.

[0026] First, in the first section 31 shown in Figures 3 and 8, a first webbing 51 having a generally trapezoidal shape in plan view is disposed on the back side of the first cover region 11. This first webbing 51 is disposed so as to span between the upper portion (210) of the first seam line and the front portion (220) of the second seam line. The rear edge of the first webbing 51 is sewn together with the first cover region 11 and the third cover region 13 and sewn together to the upper portion (210) of the first seam line (see Figure 4). The lower edge of the first webbing 51 is sewn together with the first cover region 11 and the second cover region 12 and sewn together to the front portion (220) of the second seam line, i.e., the lateral restraining region 40 (see Figure 5).

[0027] 3 and 8, a second webbing 52 having a generally rectangular shape in plan view is disposed on the back side of the second cover region 12. The second webbing 52 is disposed so as to bridge the lower portion (211) of the first seam line and the front vertical restraining region 41. The front edge of the second webbing 52 is sewn together with the left edge (front side) of the second cover region 12 and the seating-side cover region 15, and is sewn together with the front vertical restraining region 41 (see FIG. 6). The rear edge of the second webbing 52 is sewn together with the second cover region 12 and the fourth cover region 14, and is sewn together with the lower portion (211) of the first seam line (see FIG. 9). The upper end of the second webbing 52 is sewn together with the first cover region 11 and the second cover region 12, like the first webbing 51, and is sewn together with the lateral restraining region 40 (see FIG. 5).

[0028] 3 and 8, a third webbing 53 having a generally trapezoidal shape in plan view is disposed on the back side of the third cover region 13. This third webbing 53 is disposed so as to span an upper portion (210) of the first seam line and a rear portion (221) of the second seam line. The front edge of the third webbing 53 is sewn to the upper portion (210) of the first seam line, similar to the first webbing 51 (see FIG. 4). The lower edge of the third webbing 53 is sewn to the third cover region 13 and the fourth cover region 14, and is sewn to the rear portion (221) of the second seam line (see FIG. 10).

[0029] 3 and 8, a fourth webbing 54 having a generally rectangular shape in plan view is disposed on the back side of the fourth cover region 14. This fourth webbing 54 is disposed so as to bridge the lower portion (211) of the first seam line and the rear vertical restraining region 42. The rear edge of the fourth webbing 54 is sewn together with the rear edge of the fourth cover region 14 and the rear cover region 16, and is sewn and connected to the rear vertical restraining region 42 (see FIG. 7). The front edge of the fourth webbing 54 is sewn and connected to the lower portion (211) of the first seam line, similar to the second webbing 52 (see FIG. 9). The upper end of the fourth webbing 54 is sewn and connected to the rear portion (221) of the second seam line, similar to the third webbing 53 (see FIG. 10).

[0030] Referring to FIG. 8 , in the seat cover 10, the first webbing 51 to the fourth webbing 54 can be positioned to avoid the intersection 20X between the first seam line 21 and the second seam line 22. For example, in this embodiment, the planar shapes of the first webbing 51 to the fourth webbing 54 are devised to avoid overlapping with the intersection 20X. That is, the first webbing 51 and the third webbing 53 are formed into a substantially trapezoidal shape in plan, and their upper bases are positioned away from the intersection 20X. The second webbing 52 has a substantially rectangular planar shape, but has a front recess 520 cut out at a portion that would overlap the intersection 20X. Similarly, the fourth webbing 54 has a rear recess 540 cut out at a portion that would overlap the intersection 20X. In the above-described configuration, the webbing can be appropriately positioned around the intersection 20X, but there is no need to sew the webbing to the thick parts of the seat cover 10, thereby reducing the effort required for sewing.

[0031] [Reinforcement] In the seat cover 10 portion shown in FIG. 3, reinforcement portions 60 are provided at both the front and rear portions of the second seam line 22 (for convenience, the area where the reinforcement portions 60 are formed is shown by dashed lines in each drawing). The reinforcement portions 60 are portions for reinforcing the second seam line 22 to prevent it from opening. In this embodiment, the reinforcement portions 60 are formed by a front stitch portion 61 and a rear stitch portion 62 provided separately from the institch 20S (see FIGS. 5 and 10). These front stitch portions 61 and rear stitch portions 62 can be formed with a sewing thread that is more rigid than the institch 20S, and may be made of a higher-fineness or stronger material than the institch 20S. Referring to FIGS. 3 and 5, at the front portion (220) of the second seam line, the first cover portion 11 and the second cover portion 12 are sewn together with the corresponding webbing by the front stitch portion 61 as the reinforcement portion 60. This front stitch portion 61 can be provided in a range overlapping the first webbing 51 and the second webbing 52, and is arranged along the second seam line 22 at a position slightly forward from the intersection 20X. 3 and 10 , at the rear portion (221) of the second seam line, the third cover region 13 and the fourth cover region 14 are sewn together with the corresponding webbing by a rear stitch portion 62 serving as the reinforcing portion 60. This rear stitch portion 62 can be provided in a range overlapping the third webbing 53 and the fourth webbing 54, and is arranged along the second seam line 22 at a position slightly backward from the intersection 20X.

[0032] [Stretch Area] 3 and 11, the seat cover 10 has moderate stretchability and is configured so that stretch propagates in the planar direction. Therefore, in the seat cover 10, stretch propagates gradually in the planar direction when subjected to the inflation pressure of the airbag. However, in the above-described configuration, the propagation of stretch is hindered by the suppression portions (40-42). Furthermore, when the airbag 8 is ejected, the first seam line 21 quickly ruptures as described below, making it difficult for stretch to propagate across the first seam line 21. Therefore, in the seat cover 10, the first seam line 21 and the suppression portions (40-42) form multiple stretch regions (upper stretch region 71A, lower stretch region 71B, second stretch region 72) through which stretch propagates in the planar direction.

[0033] [First elongation region] In the seat cover 10 portion shown in FIG. 11, a pair of first stretch regions (upper stretch region 71A, lower stretch region 71B) are formed within each section. That is, the upper stretch region 71A is a region formed within the first section 31. In this upper stretch region 71A, surface-direction stretch propagates only within the range of the first section 31 separated by the upper portion of the first seam line (210) and the lateral restraining portion 40, i.e., the first cover portion 11 (in FIG. 11, the direction of propagation of stretch from the lateral restraining portion is indicated by arrow 81). In the upper stretch region 71A, the first webbing 51 of the first section 31 is disposed between the upper portion of the first seam line (210) and the lateral restraining portion 40, as described above. The lateral restraining portion 40 described above is an example of a restraining portion provided in the first stretch region of the present invention.

[0034] 11 is a region formed within the second section 32. In this lower stretch region 71B, the surface stretch propagates only to the range of the second section 32 divided by the lower part (211) of the first seam line, the lateral restraining portion 40, and the front longitudinal restraining portion 41, i.e., the second cover portion 12 (in FIG. 11, the direction of propagation of stretch from the front longitudinal restraining portion is indicated by the arrow 82). In the lower stretch region 71B, the second webbing 52 of the second section 32 is disposed between the lower part (211) of the first seam line and the front longitudinal restraining portion 41, and between the lower part (211) of the first seam line and the lateral restraining portion 40, as described above. The front longitudinal restraining portion 41 described above is another example of a restraining portion provided in the first stretch region of the present invention.

[0035] [Second elongation region] Furthermore, in the seat cover 10 portion shown in FIG. 11, a second stretch region 72 is formed across the third section 33 and the fourth section 34. Here, the third section 33 and the fourth section 34 are divided vertically by the rear portion (221) of the second seam line. However, the rear portion (221) of the second seam line is not anchored to the seat pad 6P, allowing for easy propagation of stretch (see FIG. 10). Therefore, in the second stretch region 72, surface-direction stretch propagates across the third section 33 and the fourth section 34, which are separated by the first seam line 21 and the rear vertical restraining portion 42 (in FIG. 11, the direction of propagation of stretch from the rear vertical restraining portion is indicated by an arrow 83). That is, in the second stretch region 72, surface-direction stretch propagates across the third cover portion 13 and the fourth cover portion 14 in the front-rear and up-down directions.

[0036] 11, a fourth webbing 54 is stretched between the lower part (211) of the first seam line and the rear vertical restraining portion 42. Furthermore, a third webbing 53 and a fourth webbing 54 are stretched between the upper part (210) of the first seam line and the rear vertical restraining portion 42. That is, the third webbing 53 and the fourth webbing 54 are sewn together via the rear part (221) of the second seam line as described above (see FIG. 10). The front edge of the third webbing 53 is sewn together to the upper part (210) of the first seam line. As a result, the third webbing 53 and the fourth webbing 54 (the webbings to be placed in the two sections) are stretched between the upper part (210) of the first seam line and the rear vertical restraining portion 42, connected together via the second seam line 22. The rear vertical restraining portion 42 corresponds to another restraining portion provided in the second stretch region of the present invention.

[0037] [Burst part behavior when airbag pops out] In the seat back 6 shown in FIG. 1, in the event of a vehicle collision, the airbag 8 inflates from the airbag device 7 and projects toward the seat occupant while tearing open the appropriate location of the cross-shaped burst portion 20. Here, the airbag 8 inflates at a position slightly below the cross-shaped burst portion 20. Therefore, the inflation pressure of the airbag 8 is first applied to the lower portion (211) of the first seam line. Note that the tearability of the lower end side of the first seam line 21 is ensured by a separate webbing 55 or the like. In this type of configuration, from the perspective of ensuring the appropriate projection of the airbag 8, it is desirable to form the burst portion 20 with two intersecting seam lines while more appropriately ensuring its tearability.

[0038] Therefore, in the vehicle seat 2 shown in Figures 3 and 8, the seat cover 10 is divided into multiple sections (first section 31 to fourth section 34) by the first seam line 21 and the second seam line 22. Each section is provided with a webbing (first webbing 51 to fourth webbing 54) that restricts stretching of the seat cover 10 in the surface direction when the airbag 8 is ejected. With the above-mentioned configuration, webbing is provided in all of the multiple sections, making it possible to control the stretching of the seat cover 10 for each section. Therefore, below, the function of each webbing will be explained in the order of when the section below the first seam line is torn and when the section above the first seam line is torn.

[0039] [Function of webbing] 3, 8, and 11, in the vehicle seat 2, the inflation pressure of the airbag is first applied to the lower part (211) of the first seam line. At this time, the stretch of the seat cover 10 portions in front and behind the lower part (211) of the first seam line can be controlled by the second webbing 52 of the second section 32 and the fourth webbing 54 of the fourth section 34. That is, in the lower stretch region 71B formed in the second section 32, stretch propagates from the front vertical restraining portion 41 to the lower part (211) of the first seam line (see the direction indicated by the arrow 82 in FIG. 11). Therefore, in the lower stretch region 71B, the second webbing 52 extending between the lower part (211) of the first seam line and the front vertical restraining portion 41 can restrain the stretch of the second cover portion 12 in the front-to-back and up-and-down directions. At this time, the second webbing 52 is also passed between the lower part (211) of the first seam line and the horizontal restraining part 40, which more reliably restrains vertical stretch of the second cover part 12. Similarly, in the fourth section 34 (below the second stretch region 72), the fourth webbing 54 passed between the lower part (211) of the first seam line and the rear vertical restraining part 42 can restrain vertical stretch of the fourth cover part 14 in the front, rear, and back directions (restraint of vertical stretch between the third and fourth sections will be described later). According to the above-mentioned configuration, the second webbing 52 and the fourth webbing 54 act to more appropriately rip open the lower part (211) of the first seam line (see FIG. 12).

[0040] 3, 8, and 11, the inflation pressure of the airbag is transmitted from the lower (211) side of the first seam line to the upper (210) side. At this time, in the seat cover 10 portion, webbing is provided in each of the first section 31 to the fourth section 34. This prevents unintended stretching of the seat cover 10 on the upper (210) side of the first seam line, prevents excessive tearing of the second seam line 22, and allows the inflation pressure of the airbag to be more appropriately transmitted to the upper (210) side of the first seam line. Furthermore, in the seat cover 10 portion, the second seam line 22 is reinforced at appropriate locations with front stitch portion 61 and rear stitch portion 62 as reinforcing portions 60. This more reliably limits the tearing range of the second seam line 22 so that it does not become excessively large (see FIG. 12). Furthermore, by limiting the tearing range of the second seam line 22, the inflation pressure (inflating force) of the airbag 8 is less likely to escape to the second seam line 22 side, and is more appropriately transmitted to the upper part (210) of the first seam line with as little loss as possible. According to the above-mentioned configuration, the inflation pressure of the airbag 8 can be applied to the first seam line 21 efficiently and quickly, which contributes to ensuring the tearing property, particularly the tearing speed.

[0041] 3, 8, and 11, at the upper part (210) of the first seam line, stretch of the portion of the seat cover 10 in front of it can be controlled by the first webbing 51 of the first section 31. That is, in the upper stretch region 71A formed in the first section 31, stretch propagates from the lateral restraining portion 40 to the upper part (210) of the first seam line (see the direction indicated by arrow 81 in FIG. 11). Therefore, in the upper stretch region 71A, the first webbing 51 stretched between the upper part (210) of the first seam line and the lateral restraining portion 40 can restrain the front-to-rear and up-and-down stretch of the first cover portion 11. At the same time, at the upper part (210) of the first seam line, stretch of the portion of the seat cover 10 in the rear of it can be controlled by the third webbing 53 of the third section 33 and the fourth webbing 54 of the fourth section 34. That is, in the second stretch region 72 spanning the third section 33 and the fourth section 34, stretch propagates from the rear vertical restraining portion 42 to the upper portion (210) of the first seam line (see the direction indicated by the arrow 83 in FIG. 11 ). Therefore, in the second stretch region 72, as described above, the third webbing 53 and the fourth webbing 54 are connected via the second seam line 22 and extend between the upper portion (210) of the first seam line and the rear vertical restraining portion 42. Therefore, in the second stretch region 72, the third webbing 53 and the fourth webbing 54 can restrain not only the front-to-rear stretch of the third cover portion 13 but also the vertical stretch spanning the third cover portion 13 and the fourth cover portion 14. According to the above-described configuration, as shown in FIG. 12 , the first seam line 21 tears open widely in the upper and lower directions of the seat due to the inflation pressure of the airbag 8, which contributes to ensuring the tearability, particularly the tear range, more appropriately.

[0042] As explained above, in this embodiment, the portion of the seat cover 10 around the burst portion 20 is divided into a plurality of sections (first section 31 to fourth section 34) by the first seam line 21 and the second seam line 22, and a webbing (any of the first webbing 51 to fourth webbing 54) is provided in each of these plurality of sections. This makes it possible to control the stretch of the portion of the seat cover 10 around the burst portion 20 for each section, and makes it possible to more reliably tear the appropriate locations of each seam line. Thus, according to this embodiment, the burst portion 20 of the seat cover 10, which is the portion from which the airbag 8 will protrude, can be formed with two intersecting seam lines while more appropriately ensuring its tearability.

[0043] Furthermore, in this embodiment, the webbing of each section (first webbing 51 to fourth webbing 54) can be more appropriately positioned according to the type of extensible region formed in the portion of the seat cover 10 around the burst portion 20. Also, in this embodiment, the first webbing 51 and second webbing 52 arranged in the upper and lower extensible regions 71A and 71B (first extensible regions) can be respectively passed between the first seam line 21 and the lateral restraining portion 40 on the second seam line 22. And in this embodiment, the reinforcing portion 60 functions to control the tearability of the second seam line 22, for example, by limiting the tear range, the tearability of the first seam line 21 can be more appropriately ensured.

[0044] The vehicle seat of this embodiment is not limited to the above-described embodiment and may take various other embodiments. In this embodiment, the configuration of the burst portion is exemplified, but the configuration of the burst portion is not intended to be limited. For example, the burst portion can be formed by forming the first seam line and the second seam line in a cross shape, or by forming only the front (or rear) portion of the second seam line and forming a horizontal T-shape. When the burst portion is formed in a horizontal T-shape, the seat cover portion around the burst portion is divided into three sections. For example, the third and fourth sections shown in FIG. 3 are formed as one section (first stretch region). In this case, a single cover portion and a single webbing can be disposed in the one section. The sections shown in FIG. 3 can also be reversed front to back, with the second stretch region provided on the front side. Second stretch regions can also be provided both in front of and behind the first seam line shown in FIG. 3. In this case, the webbing of the first and second sections can be passed between the front vertical restraining section and the first seam line. The burst portion can be formed at any suitable position on the seat cover as long as it allows the airbag to protrude toward the seat occupant. For example, the first seam line can be formed between the seat cover surface and the top panel side portion, or the first and second seam lines can be formed only on the seat cover surface. Each cover portion can be formed from multiple or single cover pieces, and the webbing can be connected to each cover portion by various methods, including stitching. Each compartment can contain one or multiple webbings, and they can be arranged so that they overlap with each other if possible. One end of the webbing contained in one compartment can be fixed to the seat frame, as long as it does not extend into another compartment.

[0045] Although the present embodiment illustrates the configuration of the restraining portion, the configuration of the restraining portion is not intended to be limited. For example, various structures such as a suspender structure, a fastener structure (line, point, or hook-and-loop fastener structure), and a hog ring structure can be appropriately selected and adopted as the configuration of the restraining portion. The first stretch region shown in FIG. 11 can have at least one restraining portion extending vertically and one restraining portion extending front-to-back (crosswise). If the first stretch region has multiple restraining portions, webbing may be connected to all of the multiple restraining portions, or the webbing may be connected to only one restraining portion selected from the multiple restraining portions. For example, in the lower stretch region shown in FIG. 3, the second webbing can be connected to at least one of the horizontal restraining portion and the front vertical restraining portion.

[0046] The first seam line need only extend vertically and can be linear, or can be inclined or curved. The second seam line also needs only to intersect with the first seam line, and the direction of intersection can be selected as appropriate. The second seam line can be provided with a reinforcing portion at least in one of its front and rear portions, or the reinforcing portion can be omitted if possible. The area where the reinforcing portion is formed can be set independently of the webbing, and if possible, it can be formed near the intersection, i.e., overlapping with the thick portion of the seat cover. The reinforcing portion can be formed continuously or intermittently along the second seam line. The reinforcing portion can be formed by stitching, gluing, welding, staples, hog rings, or other reinforcing materials.

[0047] The configuration of the vehicle seat can also be modified as needed, and the location of the airbag device can also be selected as needed. The airbag device is typically located on the outer side of the seat back (for example, the right side for a right-hand seat, or the left side for a left-hand seat) when the vehicle seat is positioned in the cabin. The seat pad can also be provided with holes that serve as a passage for the expanding airbag, or with weakened portions that are released by the inflation pressure of the airbag. The configuration of this embodiment can be applied to all vehicle seats, including those for cars, airplanes, trains, and ships. [Explanation of symbols]

[0048] 2 Vehicle seats 4 seat cushions 6 Seat back 6P seat pad 6F seat frame 6A Seating surface 6B Bank 6C Top panel side 6D Right Kamachi surface 7 Airbag device 8 Airbags 10 Seat Covers 11 First cover part 12 Second cover part 13 Third cover part 14 Fourth cover part 15 Cover part on the seating surface 16 Rear cover part 20 Burst section 20S institch 21 First suture line 22 Second suture line 20X Intersection (of the first and second suture lines) 31 First Section 32 Second Section 33 Third Section 34 Fourth Section 40 Lateral inhibitory area (an example of an inhibitory area) 40A Horizontal suspender part 400 (end of horizontal suspender) 40B Horizontal groove 40C Lateral locking part 401 Locking claw 41 Anterior vertical inhibitory area (another example of an inhibitory area) 41A Vertical suspender section 41B Vertical groove section 41C Vertical locking part 42 Posterior longitudinal inhibitory region (another inhibitory region) 41A Vertical suspender section 42A First Fastener 42B Second fastener 51 First Rikifu 52 Second force cloth 53 Third Rikifu 54 Fourth Rikifu 55 Another weave 520 Front recess 540 Rear recess 60 Reinforcement 61 Front stitching 62 Back stitching 71A Upper stretch area (first stretch area) 71B Lower stretch area (first stretch area) 72 Second stretch region

Claims

1. A vehicle seat in which a seat back serving as a backrest includes a seat cover forming the outer surface of the seat and an airbag held on the seat inner side of the seat cover, and the airbag is configured to pop out toward the seat occupant when burst portions formed at stitching points of the seat cover are released, In the burst portion, a first seam line extending in the seat up-down direction and a second seam line extending in a direction intersecting the first seam line intersect with each other, When the seat cover portion around the burst portion is divided into multiple sections by the first seam line and the second seam line, a webbing is provided in each section to restrict the stretching of the seat cover in the surface direction when the airbag is ejected.

2. The seat cover portion around the burst portion is formed with at least one region, which is a first stretch region in which stretch propagates in a surface direction within one section, and a second stretch region in which stretch propagates in a surface direction across two sections divided into upper and lower sections by the second seam line, The first stretch region is provided with at least one restraining portion that restrains stretch of the seat cover, and the webbing provided in the one section is arranged so as to be stretched between the first seam line and the restraining portion, 2. The vehicle seat according to claim 1, wherein the second stretch region is provided with another restraining portion that restrains stretch of the seat cover, and the webbing arranged in the two sections is connected to each other via the second seam line so as to extend between the first seam line and the another restraining portion.

3. 3. The vehicle seat according to claim 2, wherein the first stretchable region has the linearly formed restraining portion provided along the second seam line.

4. The vehicle seat according to any one of claims 1 to 3, wherein the second seam line is provided with a reinforcing portion that reinforces the second seam line so as to prevent the second seam line from opening.

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