Vehicle seat and method for manufacturing vehicle seat

Abstract

To provide a vehicle seat having high design quality and capable of controlling the deployment speed of a side airbag.SOLUTION: A vehicle seat 1 comprises: a bolster part 4 arranged at the side of a top plate part 30; a shoulder part 5 arranged at the upper side of the bolster part 4; a skin 6 of the bolster part 4 and the shoulder part 5; and an airbag sleeve 15 provided in the bolster part 4. The airbag sleeve 15 has: a first portion 15a arranged along a first tear line 17 which is a seam between a first skin piece 11 and a second skin piece 12; and a second portion 15b extending in such a manner as to straddle a second lateral line 20 which is a seam between the second skin piece 12 and a fourth skin piece 14. The first portion 15a is sewn to the second skin piece 12 along the first tear line 17. The second portion 15b is sewn to a pair of the second skin piece 12 and the fourth skin piece 14 in such a manner as to wrap and hold a seam allowance along the second lateral line 20.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a vehicle seat and a method for manufacturing a vehicle seat. [Background technology]

[0002] In a vehicle seat having an airbag device built into the seat back, an airbag deployment portion (hereinafter referred to as a tear line), which is a seam extending vertically on the skin of the side of the seat back, is formed in advance in order to deploy the airbag in the event of a vehicle collision. Conventionally, tear lines were formed only on the bolster portions (i.e., the portions that protrude forward and to the sides of the seat back near the sides of the body of the seat occupant) located on both sides in the width direction of the top plate portion of the seat back against which the back of the seat occupant abuts. However, in recent years, airbag devices have become larger, and designs have been developed in which tear lines are also formed on the shoulder portions (i.e., the portions that protrude forward and to the sides near the shoulders of the seat occupant) located above the bolster portions.

[0003] Seats having such designs are disclosed in, for example, the following Patent Documents 1 and 2. As shown in FIG. 9, the upholstery in the side portion of the seatback described in Patent Document 1 is composed of four upholstery pieces S1 to S4 (i.e., two upholstery pieces S1 and S2 constituting the shoulder surface, and two upholstery pieces S3 and S4 constituting the bolster surface below the shoulder). The four upholstery pieces S1 to S4 are sewn together by a horizontal line Y1 and an upper tear line Y2 and a lower tear line Y3 extending vertically. In this seatback, webbing 41, 42 are sewn to the lower upholstery pieces S3, S4 in the vicinity of the lower tear line Y3, and the webbing 41, 42 are connected to the upper upholstery pieces S1, S2 in the vicinity of the upper tear line Y2 via connecting cloths 43, 44 so that the upper tear line Y2 and the lower tear line Y3 extending vertically deploy before the horizontal line Y1 when the side airbag deploys.

[0004] 10 and 11, the seat back described in Patent Document 2 includes, as two seams, a vertical tear line 56 between a seat surface covering portion 55a (a portion covering the front surface of the seat) and a lining covering portion 55b (a portion covering the side surface of the seat) of a seat cover 55, and a horizontal line 57 intersecting the tear line 56. One end of a pair of upper and lower webbing cloths 58, 59 are sewn together at upper and lower positions sandwiching the horizontal line 57 of the vertical tear line 56. This allows the vertical tear line 56 sewn together with the webbing cloths 58, 59 to break first due to the deployment pressure of the airbag (not shown) of the airbag device 51, and then the horizontal line 57 to break. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2014-184900 A [Patent Document 2] Patent No. 3975427 Summary of the Invention [Problem to be solved by the invention]

[0006] In the seat back described in Patent Document 1, the connecting cloths 43, 44 shown in Fig. 9 extend across the lateral line Y1. Therefore, when attempting to sew the lateral line Y1 after sewing the upper and lower tear lines Y2, Y3, respectively, the connecting cloths 43, 44 will hinder the formation of a three-dimensional shape such as a hanging shape at the lateral line Y1. For example, the connecting cloths 43, 44 may collapse the seam allowance along the lateral line Y1. This causes a problem that a high design quality of the seat cannot be realized.

[0007] On the other hand, in the seat back described in Patent Document 2, the horizontal lines 57 are sewn in the same manner as the vertical tear lines 56 shown in Figures 9 and 10. Therefore, when the side airbag deploys, there is a risk that the horizontal lines 57 will tear as a whole before the tear lines 56 do, resulting in a problem that it is difficult to control the deployment speed of the side airbag.

[0008] The present invention has been made in consideration of the above circumstances, and has an object to provide a vehicle seat that has a high design quality and allows control of the deployment speed of a side airbag. [Means for solving the problem]

[0009] The vehicle seat of the present invention is a vehicle seat having an airbag device built into a seat back, the seat back comprising a top plate portion against which a seat occupant's back can come into contact, a bolster portion disposed on a side of the top plate portion, a shoulder portion disposed above the bolster portion, an upholstery constituting a surface of the bolster portion and the shoulder portion, and an airbag sleeve provided on at least one of the bolster portion and the shoulder portion for supporting the upholstery from the inside when the airbag is deployed, the upholstery comprising a first upholstery piece disposed at a position adjacent to the top plate portion in the bolster portion, a second upholstery piece disposed at a position on the bolster portion closer to the seat back than the first upholstery piece, a third upholstery piece disposed above the first upholstery piece in the shoulder portion, and a fourth upholstery piece disposed above the second upholstery piece in the shoulder portion, the third upholstery piece and the fourth upholstery piece are sewn together along a first tear line extending in the vertical direction of the seat back, the third upholstery piece and the fourth upholstery piece are sewn together along a second tear line extending in the vertical direction so as to be continuous with the first tear line, the first upholstery piece and the third upholstery piece are sewn together along a first lateral line extending in a cross direction intersecting the first tear line, and the second upholstery piece and the fourth upholstery piece are sewn together along a second lateral line extending in the cross direction so as to be continuous with the first lateral line, the airbag sleeve has a first portion disposed along the first tear line or the second tear line and a second portion extending across the first lateral line or the second lateral line, the first portion is sewn to at least one of the first to fourth upholstery pieces so as to be continuous with the first lateral line, N Following seam allowance an overlapping portion where the ends of the first skin piece and the third skin piece overlap each other, or an overlapping portion where the ends of the second skin piece and the fourth skin piece overlap each other at a seam allowance along the second horizontal line Wrap and clamp In this state, At least one of the pair of the first skin piece and the third skin piece, or the pair of the second skin piece and the fourth skin piece Polymerization part of The present invention is characterized in that it is sewn to the

[0010] According to this configuration, the second portion of the airbag sleeve is aligned along the first lateral line. N Following seam allowance an overlapping portion where the ends of the first skin piece and the third skin piece overlap, or an overlapping portion where the ends of the second skin piece and the fourth skin piece overlap at a seam allowance along a second horizontal line Wrap and clamp In this state, At least one of a pair of a first skin piece and a third skin piece, or a pair of a second skin piece and a fourth skin piece Polymerization part of This allows the first horizontal line or the second horizontal line, which is the boundary between the shoulder portion and the bolster portion, to be sewn into a three-dimensional shape that appears to be suspended, making it possible to provide a seat with high design quality.

[0011] In addition, because the second portion of the airbag sleeve is sewn across (crosses) the seam allowance along the first horizontal line or the second horizontal line, the tear strength of the first horizontal line or the second horizontal line is increased, making it possible to prevent the first horizontal line or the second horizontal line from breaking before the first and second tear lines, allowing the airbag to deploy smoothly as intended, and thus making it possible to control the deployment speed. Moreover, according to the above configuration, the overlapping portion where the ends of the skin pieces overlap at the seam allowance along the first or second horizontal line is sewn not only by the first or second horizontal line but also by the second portion of the airbag sleeve. In other words, the overlapping portion is doubly sewn at two different locations. This makes it possible to reliably prevent the first or second horizontal line from breaking when the airbag is deployed.

[0012] In the above vehicle seat, it is preferable that the airbag device is housed in the bolster portion, the first portion is sewn to the second upholstery piece along the first tear line, and the second portion is sewn to the set of the second upholstery piece and the fourth upholstery piece so as to wrap and hold a seam allowance along the second lateral line.

[0013] According to this configuration, it is possible to control the deployment speed more accurately. That is, in a configuration in which the airbag device is housed in the bolster, when the airbag deploys, the most pressure is applied to the second skin piece, which is located on the side farther from the top panel, i.e., the side that constitutes the side of the seat, among the first and second skin pieces that constitute the surface of the bolster, and the first tear line extending in the vertical direction where the seam of the second skin piece is located and the second horizontal line extending in the cross direction that crosses the vertical direction are easily torn. Therefore, in the above configuration, the first portion of the airbag sleeve is sewn to the second skin piece so as to be along the first tear line, so that the first tear line is more easily broken when the airbag deploys, while the second portion is sewn to the set of the second skin piece and the fourth skin piece so as to wrap and hold the seam along the second horizontal line, so that it is possible to prevent the second horizontal line from breaking before the first tear line when the airbag deploys.

[0014] In the above vehicle seat, it is preferable that the second portion is sewn to an overlapping portion where ends of the first upholstery piece and the third upholstery piece overlap at a seam allowance along the first horizontal line, or an overlapping portion where ends of the second upholstery piece and the fourth upholstery piece overlap at a seam allowance along the second horizontal line, in a state in which the second portion is wrapped around and sandwiched between the overlapping portion.

[0015] According to this configuration, the overlapping portion where the ends of the skin pieces overlap at the seam allowance along the first or second horizontal line is not only sewn by the first or second horizontal line, but also by the second portion of the airbag sleeve. In other words, the overlapping portion is doubly sewn at two different locations. This makes it possible to reliably prevent the first or second horizontal line from breaking when the airbag is deployed.

[0016] The manufacturing method of the vehicle seat of the present invention is a vehicle seat having an airbag device built in a seat back, the seat back comprising a top plate portion against which the back of a seated occupant abuts, a bolster portion disposed on a side of the top plate portion, a shoulder portion disposed above the bolster portion, an upholstery forming the surfaces of the bolster portion and the shoulder portion, and an airbag sleeve provided on at least one of the bolster portion and the shoulder portion and supporting the upholstery from the inside when the airbag is deployed. , No. 1 piece and 2 parts and An airbag sleeve having a skin piece preparing step of preparing, as components of the skin, a first skin piece disposed at a position adjacent to the top plate portion in the bolster portion, a second skin piece disposed at a position on the bolster portion closer to the top plate portion than the first skin piece, a third skin piece disposed above the first skin piece in the shoulder portion, and a fourth skin piece disposed above the second skin piece in the shoulder portion; 、 At least one of the first to fourth skin pieces along a first tear line where the first upholstery piece and the second upholstery piece are sewn together and extend in the longitudinal direction of the seat back, or along a second tear line where the third upholstery piece and the fourth upholstery piece are sewn together and extend in the longitudinal direction of the seat back, a first partial sewing step of sewing the first cover piece and the second cover piece together, the first partial sewing step being a ... The above The third skin piece and the fourth skin piece are sewn together along a first tear line, and the third skin piece and the fourth skin piece are sewn together along a longitudinal direction. The above a tear line sewing step of sewing together along a second tear line; a lateral line sewing step of sewing together the first skin piece and the third skin piece along a first lateral line extending in a cross direction that crosses the first tear line and sewing together the second skin piece and the fourth skin piece along a second lateral line extending in the cross direction so as to be continuous with the first lateral line; N Following seam allowance An overlapping portion where the ends of the first skin piece and the third skin piece overlap each other, or an overlapping portion where the ends of the second skin piece and the fourth skin piece overlap each other at a seam allowance along the second horizontal line Wrap and hold In this state, At least one of the pair of the first skin piece and the third skin piece, or the pair of the second skin piece and the fourth skin piece The polymerized portion ofand a second partial sewing step of sewing the first partial skin piece to at least one of the first to fourth skin pieces along the first tear line or the second tear line in the first partial sewing step.

[0017] According to this feature, after a first portion sewing step of sewing a first portion of the airbag sleeve to at least one of the first to fourth skin pieces along the first tear line or the second tear line, a second portion sewing step of sewing a second portion of the airbag sleeve to at least one of the first to fourth skin pieces along the first lateral line or the second tear line is performed. N Following seam allowance In the overlapping portion where the ends of the first skin piece and the third skin piece overlap, or in the overlapping portion where the ends of the second skin piece and the fourth skin piece overlap at the seam allowance along the second horizontal line, Wrap and hold In this state, At least one of a pair of a first skin piece and a third skin piece, or a pair of a second skin piece and a fourth skin piece Polymerization part of This allows the first horizontal line or the second horizontal line, which is the boundary between the shoulder and bolster sections, to be sewn into a three-dimensional shape that appears to be suspended, making it possible to manufacture a seat with high design quality.

[0018] In addition, in the second portion sewing process, the second portion of the airbag sleeve is sewn across (crosses) the seam allowance along the first horizontal line or the second horizontal line, which increases the tear strength of the first horizontal line or the second horizontal line and prevents the first horizontal line or the second horizontal line from breaking before the first tear line and the second tear line, allowing the airbag to deploy smoothly as intended. As a result, it becomes possible to manufacture a seat whose deployment speed can be controlled. Moreover, according to the above manufacturing method, in the second portion sewing step, the overlapping portion where the ends of the skin pieces overlap at the seam allowance along the first or second horizontal line is not only sewn by the first or second horizontal line, but also by the second portion of the airbag sleeve. In other words, the overlapping portion is doubly sewn at two different locations. This makes it possible to reliably prevent the first or second horizontal line from breaking when the airbag is deployed.

[0019] In the above-mentioned method for manufacturing a vehicle seat, the first portion of the airbag sleeve can be overlapped with at least one of the first to fourth skin pieces along the first tear line or the second tear line, and the first portion sewing step and the tear line sewing step can be performed simultaneously.

[0020] This makes it possible to simultaneously perform sewing of the first portion of the airbag sleeve and sewing along the tear line between the skin pieces, improving workability. Effect of the Invention

[0021] The vehicle seat of the present invention has a high designability and allows control of the deployment speed of the side airbag.

[0022] According to the method for manufacturing a vehicle seat of the present invention, it is possible to manufacture a vehicle seat that has a high design quality and allows control of the deployment speed of a side airbag. [Brief description of the drawings]

[0023] [Figure 1] 1 is a perspective view showing an overall configuration of a vehicle seat according to an embodiment of the present invention; [Diagram 2] FIG. 2 is a cross-sectional view taken along line II-II in FIG. [Diagram 3] FIG. 2 is a side view of the seat back of FIG. [Figure 4] 2 is an enlarged view of a portion A of the sheet showing the sewn portions of the first to fourth skin pieces in FIG. [Diagram 5] 2 is a perspective view of the back surface (inner side) of the cover of the seat back in FIG. 1 and first and second airbag sleeves. FIG. [Figure 6] 6 is an enlarged view of the first airbag sleeve and its surroundings in FIG. 5. [Figure 7] FIG. 7 is a cross-sectional view taken along line VII-VII in FIG. [Figure 8] FIG. 8 is a cross-sectional view taken along line VIII-VIII in FIG. [Figure 9] 1 is an enlarged view of a stitched portion of a cover piece of a seat back described in Patent Document 1, which is an example of a conventional seat. [Figure 10] FIG. 1 is a side view of a seat back described in Patent Document 2, which is another example of a conventional seat. [Figure 11] FIG. 11 is a diagram showing a state in which the airbag of the seat back in FIG. 10 is deployed. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of the present invention will now be described in detail with reference to the accompanying drawings, in which the vehicle longitudinal direction X, vehicle width direction Y, and vertical direction Z are appropriately indicated by arrows.

[0025] 1 (hereinafter referred to as seat 1) has an airbag device 9 built into a seat back 3. Specifically, the seat 1 includes a seat cushion 2 against which the buttocks of a seated occupant can come into contact, a seat back 3 against which the back of the seated occupant can come into contact, and the airbag device 9.

[0026] As shown in Figures 1 to 5, the seat back 3 comprises a top panel portion 30 that faces toward the front of the vehicle X1 and against which the back of a seated occupant can abut, a pair of bolster portions 4 arranged adjacent to each other on either side of the top panel portion 30 in the vehicle width direction Y, a pair of shoulder portions 5 arranged on the upper side of the pair of bolster portions 4, a skin 6 that forms the surfaces of the bolster portions 4 and the shoulder portions 5, and a first airbag sleeve 15 and a second airbag sleeve 16 that are provided on at least one of the bolster portion 4 and the shoulder portion 5 (in this embodiment, the bolster portion 4) and that support the skin 6 from the inside when the airbag is deployed.

[0027] The bolster portion 4 is a vertically long cushion-like portion that protrudes forward and to the side of the seat back 3 near the sides of the body of the seated occupant. As shown in Figs. 1 to 3, the bolster portion 4 of this embodiment is composed of a first skin piece 11 and a second skin piece 12 of a skin 6 described below, a cushion pad 7 covered by the first skin piece 11 and the second skin piece 12, and a frame 8 that supports the cushion pad 7. An airbag device 9 is housed in the bolster portion 4 on the outer side in the vehicle width direction of the pair of bolster portions 4 and is fixed to the frame 8.

[0028] The shoulder portion 5 has a portion that protrudes forward and to the side near the shoulder of the seated occupant. In this embodiment, the pair of shoulder portions 5 extend in the width direction Y and are integrated together, but may be separated from each other.

[0029] The surface portions of the bolster portion 4 and shoulder portion 5 on the side where the airbag device 9 is housed (the right side in FIG. 1) are constituted by a skin 6 made by sewing together a number of skin pieces, as shown in FIGS. 1-2 and 5-6.

[0030] As shown in Figs. 1-2 and 4-6, the skin 6 includes four skin pieces 11-14. Specifically, the skin 6 includes a first skin piece 11 disposed at a position adjacent to the top panel 30 in the bolster portion 4 (i.e., on the top panel side), a second skin piece 12 disposed at a position on the bolster portion 4 on the seat back side farther from the top panel 30 than the first skin piece 11 (i.e., on the side constituting the side surface of the seat back 3), a third skin piece 13 disposed above the first skin piece 11 in the shoulder portion 5 (i.e., on the top panel side), and a fourth skin piece 14 disposed above the second skin piece 12 in the shoulder portion 5 (i.e., on the seat back side).

[0031] First, the sewing of the bolster portion 4 will be described. As shown in Figs. 1-2 and 4-7, the first skin piece 11 and the second skin piece 12 are sewn together along a first tear line 17 extending in the vertical direction D1 of the seat back 3. Specifically, as shown in Fig. 7, the end 11a on the side surface side of the first skin piece 11 and the end 12a of the second skin piece 12 facing the end 11a are sewn together with a sewing thread 22 to form the first tear line 17 extending in the vertical direction D1. In addition, on the inside of the folded end 12a of the second skin piece 12, a first portion 15a of a first airbag sleeve 15 described later is sewn to the end 12a with the sewing thread 22.

[0032] Additionally, a third skin piece 13 and a fourth skin piece 14 are sewn together at the shoulder portion 5. These skin pieces are sewn together along a second tear line 18 that extends in the longitudinal direction D1 so as to be continuous with the first tear line 17, as shown in Figs.

[0033] 4 to 6, the first upholstery piece 11 and the third upholstery piece 13, which are aligned in the up-down direction Z, are sewn together along a first lateral line 19 that extends in the lateral direction D2 (intersecting direction) intersecting the first tear line 17. Note that the first lateral line 19 extends downward as it approaches the top plate portion 30 of the seat back 3, as shown in Fig. 6, and forms a sewn portion between the first upholstery piece 11 and the upholstery piece 31 of the top plate portion 30.

[0034] The horizontal direction D2 may be any direction intersecting the vertical direction D1, and may not only be a direction perpendicular to the vertical direction D1, but also may be slightly inclined from the perpendicular direction.

[0035] Furthermore, the second skin piece 12 and the fourth skin piece 14 aligned in the up-down direction Z are sewn together along a second lateral line 20 extending in the lateral direction D2 so as to be continuous with the first lateral line 19. Specifically, as shown in Fig. 8, an upper end portion 12b of the second skin piece 12 and a lower end portion 14a of the fourth skin piece 14 facing thereto are sewn together with a sewing thread 23 to form the second lateral line 20 extending in the lateral direction D2.

[0036] As shown in FIG. 4, the two tear lines (first tear line 17 and second tear line 18) extending in the vertical direction D1 and the two horizontal lines (first horizontal line 19 and second horizontal line 20) extending in the horizontal direction D2 are arranged to converge at a gathering point 21.

[0037] 2-3 and 5-6, in this embodiment, one end of the first airbag sleeve 15 (specifically, a first portion 15a described below) is sewn to the second skin piece 12 with a sewing thread 22 (see FIG. 7) so as to sandwich a first tear line 17 extending in the vertical direction D1, and one end of the second airbag sleeve 16 (specifically, the left end in FIGS. 5-6) is sewn to the first skin piece 11 with the above-mentioned sewing thread 22.

[0038] As shown in Fig. 2, the first airbag sleeve 15 is located inside the second skin piece 12 and extends to pass on the outer side Y1 of the airbag device 9 in the vehicle width direction Y, with one end (specifically, the first portion 15a in Figs. 5 to 7) fixed near the first tear line 17 of the second skin piece 12 and the other end fixed to the frame 8. On the other hand, the second airbag sleeve 16 extends to pass on the inner side Y2 of the airbag device 9 in the vehicle width direction Y, with one end fixed near the first tear line 17 of the first skin piece 11 and the other end fixed to the frame 8. There is no cushion pad 7 on the outer side Y1 of the airbag device 9 in the vehicle width direction Y (the seat back side of the seat 1), and the airbag device 9 is shielded from the outside of the seat by only the second skin piece 12 and the first airbag sleeve 15.

[0039] 5 to 8, the first airbag sleeve 15 of this embodiment specifically includes a first portion 15a that extends in a direction along the first tear line 17 and ensures rupture of the first tear line 17 when the airbag is deployed, a second portion 15b that extends across the second lateral line 20 (i.e., extends in a direction intersecting the second lateral line 20) and relatively delays the rupture of the second lateral line 20 when the airbag is deployed, and a third portion 15c that is fixed to the frame 8 side (see FIG. 2). The first airbag sleeve 15 is included in the concept of an airbag sleeve of the present invention.

[0040] As shown in FIG. 7, the first portion 15a is sewn to the back surface side of the second skin piece 12 along the first tear line 17.

[0041] 8, the second portion 15b is sewn to the set of the second skin piece 12 and the fourth skin piece 14 so as to wrap and hold the seam along the second horizontal line 20. Specifically, the second portion 15b is sewn to the overlapping portion 25, where the end portion 12b of the second skin piece 12 and the end portion 14a of the fourth skin piece 14 overlap, by the sewing thread 24 in a state in which the second portion 15b wraps and holds the overlapping portion 25 at the seam along the second horizontal line 20. As a result, a strong enveloping portion 26 (see FIGS. 5 to 6 and 8) is formed in which the second portion 15b wraps and holds the overlapping portion 25.

[0042] The sheet 1 configured as above is manufactured by the following steps (I) to (V).

[0043] (I) A skin piece preparation step for preparing, as components of the skin 6 that constitutes the surface portion of the bolster portion 4 and the shoulder portion 5, a first skin piece 11 arranged adjacent to the top plate portion 30 of the bolster portion 4, a second skin piece 12 arranged on the bolster portion 4 at a position on the side farther from the top plate portion 30 than the first skin piece 11, a third skin piece 13 arranged above the first skin piece 11 on the shoulder portion 5, and a fourth skin piece 14 arranged above the second skin piece 12 on the shoulder portion 5.

[0044] (II) A first portion sewing process for sewing the first portion 15a of the first airbag sleeve 15 to at least one of the first to fourth skin pieces 11 to 14, in this embodiment, the second skin piece 12, along the first tear line 17.

[0045] (III) a tear line sewing process in which the first and second skin pieces 11, 12 of the bolster portion 4 are sewn together along a first tear line 17 extending in the longitudinal direction D1 of the seat back 3, and the third and fourth skin pieces 13, 14 of the shoulder portion 5 are sewn together along a second tear line 18 extending in the longitudinal direction D1.

[0046] (IV) a lateral line sewing step of sewing the first skin piece 11 and the third skin piece 13 together along a first lateral line 19 extending in the lateral direction D2 intersecting the first tear line 17, and sewing the second skin piece 12 and the fourth skin piece 14 together along a second lateral line 20 extending in the lateral direction D2 so as to be continuous with the first lateral line 19.

[0047] (V) A second portion sewing step of sewing the second portion 15b of the first airbag sleeve 15 to the set of the second skin piece 12 and the fourth skin piece 14 so as to wrap and hold the seam allowance along the second horizontal line 20 (specifically, the overlapping portion 25 in FIG. 8 ).

[0048] In addition, the above (II) first portion sewing step and (III) tear line sewing step may be performed simultaneously in a state where first portion 15a of first airbag sleeve 15 is overlapped with at least one of first to fourth skin pieces 11 to 14 along first tear line 17 or second tear line 18.

[0049] (Features of this embodiment) (1) 5-6 and 8, in the seat 1 of this embodiment, the second portion 15b of the airbag sleeve is sewn to the set of the second skin piece 12 and the fourth skin piece 14 so as to wrap and hold the seam allowance along the second lateral line 20. This allows the second lateral line 20, which is the boundary between the shoulder portion 5 and the bolster portion 4, to have a three-dimensional shape as if it were suspended, making it possible to provide a seat with a high level of design.

[0050] In addition, because the second portion 15b of the first airbag sleeve 15 is sewn so as to straddle (intersect) the seam allowance along the second lateral line 20, the tear strength of the second lateral line 20 is increased, making it possible to prevent the second lateral line 20 from breaking before the first tear line 17 and the second tear line 18, allowing the airbag built into the airbag device 9 to be deployed smoothly as intended. As a result, it becomes possible to control the deployment speed of the airbag.

[0051] Furthermore, in the seat 1 of this embodiment, fewer airbag sleeves are required compared to a conventional seat structure in which airbag sleeves (weave cloths) are provided at two locations, above and below a lateral line (see Figs. 10-11). Also, the first airbag sleeve 15 only needs to be sewn at two locations, one tear line (first tear line 17) and one lateral line (second lateral line 20), and there is no need to change the thread used to sew the first airbag sleeve 15, resulting in good workability.

[0052] (2) In the seat 1 of this embodiment, as shown in Figures 1 and 2, the airbag device 9 is housed in the bolster portion 4. As shown in Figures 5 to 7, the first portion 15a of the first airbag sleeve 15 is sewn to the second upholstery piece 12 along the first tear line 17. The second portion 15b is sewn to the set of the second upholstery piece 12 and the fourth upholstery piece 14 so as to wrap and hold the seam along the second lateral line 20.

[0053] According to this configuration, it is possible to control the deployment speed more accurately. That is, in a configuration in which the airbag device 9 is housed in the bolster portion 4, when the airbag device 9 deploys, the most pressure is applied to the second skin piece 12, which is located on the side of the seat farther from the top plate portion 30, among the first skin piece 11 and the second skin piece 12 that constitute the surface portion of the bolster portion 4, and the first tear line 17 extending in the vertical direction D1 where the seam of the second skin piece 12 is located and the second horizontal line 20 extending in the horizontal direction D2 (crossing direction) that intersects with the vertical direction D1 are easily torn. Therefore, in the above configuration, first, the first portion 15a of the first airbag sleeve 15 is sewn to the second skin piece 12 so as to be aligned with the first tear line 17, thereby making the first tear line 17 more likely to break when the airbag deploys. Furthermore, since the second portion 15b is sewn to the set of the second skin piece 12 and the fourth skin piece 14 so as to encase and hold the seam allowance along the second horizontal line 20, it is possible to prevent the second horizontal line 20 from breaking before the first tear line 17 breaks when the airbag is deployed.

[0054] (3) In the sheet 1 of this embodiment, as shown in Figures 5-6 and 8, the second portion 15b of the first airbag sleeve 15 is sewn to the overlapping portion 25 by a sewing thread 24 in a state in which the second portion 15b wraps around and holds an overlapping portion 25 where the ends 12b, 14a of the second skin piece 12 and the fourth skin piece 14 overlap each other at the seam allowance along the second horizontal line 20.

[0055] According to this configuration, the overlapping portion 25 where the ends 12b, 14a of the second skin piece 12 and the fourth skin piece 14 overlap at the seam allowance along the second horizontal line 20 is not only sewn by the sewing thread 23 at the second horizontal line 20, but also sewn by the sewing thread 24 so that the second portion 15b of the first airbag sleeve 15 wraps around and holds the overlapping portion 25. In other words, the overlapping portion 25 is doubly sewn at two different positions. This makes it possible to reliably prevent the second horizontal line 20 from breaking when the airbag is deployed.

[0056] (4) In the manufacturing method of the seat of this embodiment, after a first portion sewing step in which the first portion 15a of the first airbag sleeve 15 is sewn to the second upholstery piece 12 along the first tear line 17, in a second portion sewing step, the second portion 15b of the airbag sleeve is sewn to the set of the second upholstery piece 12 and the fourth upholstery piece 14 so as to wrap and clamp the seam allowance along the second lateral line 20.

[0057] As a result, similar to (1) above, it is possible to give the first horizontal line 19 or the second horizontal line 20, which is the boundary between the shoulder portion 5 and the bolster portion 4, a three-dimensional shape in which it is suspended, making it possible to produce a seat with high design quality.

[0058] Furthermore, in the second portion sewing process, the second portion 15b of the first airbag sleeve 15 is sewn so as to straddle (cross) the seam allowance along the second horizontal line 20, so similarly to (1) above, the tear strength of the second horizontal line 20 is increased and it is possible to prevent the second horizontal line 20 from breaking before the first tear line 17 and the second tear line 18, which are vertical lines, allowing the airbag of the airbag device 9 to deploy smoothly as intended. As a result, it is possible to manufacture a seat whose deployment speed can be controlled.

[0059] Furthermore, in the above manufacturing method, similarly to (1) above, fewer airbag sleeves are used, and the first airbag sleeve 15 only needs to be sewn in two places, one tear line and one lateral line, and there is no need to change the thread used to sew the first airbag sleeve 15, making the method easier to work with.

[0060] In the above-described method for manufacturing a vehicle seat, the first portion sewing step and the tear line sewing step can be performed simultaneously in a state in which the first portion 15a of the airbag sleeve 15 is overlapped with at least one of the first to fourth skin pieces 11 to 14 along the first tear line 17 or the second tear line 18. This makes it possible to simultaneously perform sewing of the first portion 15a of the airbag sleeve 15 and sewing along the tear line 17 between the skin pieces 11 and 12 (or sewing along the tear line 18 between the skin pieces 13 and 14), improving workability.

[0061] (Modification) (A) In the above embodiment, as shown in Figures 2 and 3, the first airbag sleeve 15 is provided in the bolster portion 4, but the present invention is not limited to this, and the first airbag sleeve 15 may be provided in the shoulder portion 5. Furthermore, the first airbag sleeve 15 may be provided in both the bolster portion 4 and the shoulder portion 5. In this case, it is possible to achieve the same effects as those of (1) to (4) above.

[0062] (B) In addition, in the above embodiment, the skin 6 is composed of four skin pieces 11 to 14, but the number of skin pieces is not limited to this, and depending on the design of the seat 1, it may be composed of five or more skin pieces.

[0063] (C) Furthermore, in the above embodiment, as shown in Figs. 5 and 6, the first portion 15a of the first airbag sleeve 15 is sewn to the second skin piece 12 on the lining side along the first tear line 17, and the second portion 15b is sewn to the set of the second skin piece 12 and the fourth skin piece 14 so as to encase and hold the seam allowance along the second lateral line 20, but the present invention is not limited to this.

[0064] In the present invention, first portion 15a is sewn to at least one of the first to fourth skin pieces 11 to 14 along first tear line 17 or second tear line 18, and second portion 15b is sewn to at least one of the set of first skin piece 11 and third skin piece 13, or the set of second skin piece 12 and fourth skin piece 14, so as to wrap and hold the seam allowance along first horizontal line 19 or second horizontal line 20.

[0065] Therefore, in the modified embodiment of the present invention, the first portion 15a and the second portion 15b of the first airbag sleeve 15 may be changed to various arrangements as follows.

[0066] For example, the first portion 15a may be sewn to the first skin piece 11 on the top panel side along the first tear line 17. Alternatively, when two first airbag sleeves 15 are provided across the first tear line 17, the first portion 15a may be sewn to the first skin piece 11 on the top panel side and the second skin piece 12 on the hem side along the first tear line 17. Furthermore, when the first airbag sleeve 15 is provided in the shoulder portion 5, the first portion 15a may be sewn to either the third skin piece 13 or the fourth skin piece 14 along the second tear line 18. Furthermore, when two first airbag sleeves 15 are provided, the first portion 15a may be sewn to each of the third skin piece 13 and the fourth skin piece 14.

[0067] Also, the second portion 15b may be sewn to the set of the first skin piece 11 and the third skin piece 13 so as to wrap and hold the seam allowance along the first horizontal line 19. Alternatively, when two first airbag sleeves 15 are provided, one of the two second portions 15b may be sewn to the set of the first skin piece 11 and the third skin piece 13 so as to wrap and hold the seam allowance along the first horizontal line 19, and the other may be sewn to the set of the second skin piece 12 and the fourth skin piece 14 so as to wrap and hold the seam allowance along the second horizontal line 20.

[0068] As described above, even if the first portion 15a and the second portion 15b of the first airbag sleeve 15 are arranged in various ways, as long as the first portion 15a is sewn to one of the upholstery pieces 11 to 14 along the first tear line 17 or the second tear line 18, and the second portion 15b is sewn to the two upholstery piece sets 11, 13 or 12, 14, wrapping around the seam allowance along the first horizontal line 19 or the second horizontal line 20, it is possible to achieve the same effects as those described above in (1) to (4). [Explanation of symbols]

[0069] 1 sheet 3 Seat back 4 Bolster section 5 Shoulder 6 Epidermis 9. Airbag device 11 First skin piece 12 Second skin piece 13 Third skin piece 14 Fourth Skin Piece 15 First airbag sleeve (airbag sleeve) 15a Part 1 15b Part 2 16 Second Airbag Sleeve 17 First Tier Line 18 Second Tier Line 19 First horizontal line 20 Second horizontal line 22, 23, 24 Sutures 25 Polymerization part 26 Wrapping part 30 Top plate

Claims

1. In a vehicle seat having an airbag device built into the seat back, the seat back comprises a top panel portion against which the back of a seated occupant can come into contact, a bolster portion disposed on a side of the top panel portion, a shoulder portion disposed above the bolster portion, a skin forming a surface of the bolster portion and the shoulder portion, and an airbag sleeve provided on at least one of the bolster portion and the shoulder portion and supporting the skin from the inside when the airbag is deployed; The skin includes a first skin piece disposed at a position adjacent to the top plate in the bolster portion, a second skin piece disposed at a position on the bolster portion farther from the top plate than the first skin piece, a third skin piece disposed above the first skin piece in the shoulder portion, and a fourth skin piece disposed above the second skin piece in the shoulder portion. The first skin piece and the second skin piece are sewn together along a first tear line extending in a longitudinal direction of the seat back, the third skin piece and the fourth skin piece are sewn together along a second tear line extending in the longitudinal direction so as to be continuous with the first tear line, The first skin piece and the third skin piece are sewn together along a first lateral line extending in a cross direction that crosses the first tear line, the second skin piece and the fourth skin piece are sewn together along a second horizontal line extending in the intersecting direction so as to be continuous with the first horizontal line, the airbag sleeve has a first portion disposed along the first tear line or the second tear line and a second portion extending across the first lateral line or the second lateral line, the first portion is sewn to at least one of the first to fourth skin pieces along the first tear line or the second tear line; and the second portion is sewn to at least one overlapping portion of the set of the first and third skin pieces or the set of the second and fourth skin pieces in a state in which the second portion wraps around and holds an overlapping portion where ends of the first and third skin pieces overlap at a seam allowance along the first horizontal line, or an overlapping portion where ends of the second and fourth skin pieces overlap at a seam allowance along the second horizontal line; A vehicle seat comprising:

2. The vehicle seat according to claim 1, The airbag device is housed in the bolster portion, the first portion is sewn to the second skin piece along the first tear line; The second portion is sewn to the set of the second skin piece and the fourth skin piece so as to wrap and hold the seam allowance along the second horizontal line. A vehicle seat comprising:

3. A method for manufacturing a vehicle seat having an airbag device built into a seat back, the seat back comprising: a top plate portion against which a seat occupant's back abuts; a bolster portion disposed on a side of the top plate portion; a shoulder portion disposed above the bolster portion; a skin forming the surfaces of the bolster portion and the shoulder portion; and an airbag sleeve provided on at least one of the bolster portion and the shoulder portion and supporting the skin from the inside when the airbag is deployed, the airbag sleeve having a first portion and a second portion, a skin piece preparation process for preparing, as components of the skin, a first skin piece disposed at a position adjacent to the top plate in the bolster portion, a second skin piece disposed at a position on the bolster portion farther from the top plate than the first skin piece, a third skin piece disposed above the first skin piece in the shoulder portion, and a fourth skin piece disposed above the second skin piece in the shoulder portion; a first portion sewing step of sewing the first portion of the airbag sleeve to at least one of the first to fourth skin pieces along a first tear line where the first skin piece and the second skin piece are sewn together and extending in a longitudinal direction of the seat back, or along a second tear line where the third skin piece and the fourth skin piece are sewn together and extending in the longitudinal direction; a tear line sewing process of sewing the first skin piece and the second skin piece together along the first tear line extending in a longitudinal direction of the seat back, and sewing the third skin piece and the fourth skin piece together along the second tear line extending in the longitudinal direction; a lateral line sewing step of sewing the first skin piece and the third skin piece together along a first lateral line extending in a cross direction that crosses the first tear line, and sewing the second skin piece and the fourth skin piece together along a second lateral line extending in the cross direction so as to be continuous with the first lateral line; a second part sewing process of sewing the second part of the airbag sleeve to at least one of an overlapping part where ends of the first upholstery piece and the third upholstery piece overlap each other at a seam allowance along the first horizontal line or an overlapping part where ends of the second upholstery piece and the fourth upholstery piece overlap each other at a seam allowance along the second horizontal line while wrapping and sandwiching the second part of the airbag sleeve to at least one of the overlapping parts of the set of the first upholstery piece and the third upholstery piece or the set of the second upholstery piece and the fourth upholstery piece; having In the first partial sewing step, the first tear line is sewn to at least one of the first to fourth skin pieces along the first tear line or the second tear line. Characterized by A method for manufacturing a vehicle seat.

4. The method for manufacturing a vehicle seat according to claim 3, performing the first portion sewing step and the tear line sewing step simultaneously in a state where the first portion of the airbag sleeve is overlapped with at least one of the first to fourth skin pieces along the first tear line or the second tear line; A method for manufacturing a vehicle seat comprising the steps of:

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