Skin material for seat, and vehicle seat

Abstract

A two-sheet skin piece (2) of a skin material 1 for a seat includes a first layer (3) and a second layer (4) which are stitched together at a stitched portion (7). A folded-back edge portion (6) is composed of a seam allowance (8) constituting the edge portion side of the folded-back edge portion (6), and a base portion (9) constituting the base side of the folded-back edge portion (6). The seam allowance (8) of the folded-back edge portion (6) of the skin piece (2) is folded back so as to overlap the base portion (9), with the stitched portion (7) as a starting point. A seam allowance edge portion (10) is overlaid onto the second layer (4) of the base portion (9) in the folded-back edge portion (6) of the skin piece (2). The thickness of the second layer (4a) of the seam allowance (8) and the thickness of the second layer (4b) of the base portion (9) are set to be less than the thickness of the second layer (4c) of a central portion (5) of the skin piece (2).

Description

Seat covering material and vehicle seat

[0001] The present invention relates to a seat covering material and a vehicle seat provided with the same.

[0002] BACKGROUND ART Various seat covering materials that constitute the surface of automobile seats and the like have been proposed.

[0003] The seat covering material described in Patent Document 1 has two pieces of trim cover material, and is constructed by sewing together the ends of these trim cover materials.

[0004] Each trim cover material has a laminated structure in which a surface layer material (skin material) constituting the surface side layer and a cushioning material (wadding material) constituting the back side layer are laminated together.

[0005] The cushioning material is removed from the end of each trim / cover material, leaving only the surface layer. The surface layers at the ends of the two trim / cover materials are sewn together with their surfaces in contact with each other. At the end of each trim / cover material, the seam allowance, which is the portion of the surface layer closer to the tip than the sewn portion, is folded back so that it overlaps the back surface of the portion of the surface layer closer to the base than the sewn portion.

[0006] In the above structure, the cushioning material on the back side of the surface layer is removed at the end of the trim / cover material. Furthermore, the surface layer that forms the seam allowance on the tip side of the seam is folded back so that it overlaps the back side of the surface layer on the base side of the seam. Therefore, at the end of the trim / cover material, the end of the folded-back surface layer on the tip side directly contacts the back side of the surface layer on the base side, causing the outline of the tip side to be visible on the surface layer on the base side, resulting in poor appearance of the trim / cover material.

[0007] On the other hand, if the cushioning material on the back side of the surface material is not removed at the end of the trim / cover material and cushioning material of the same thickness as the other parts of the trim / cover material is present, there is a problem that the thickness of the cushioning material will cause poor appearance at the part where the seam allowance is folded back.

[0008] Patent No. 5642491

[0009] The present invention has been made in view of the above circumstances, and has as its object to provide a seat covering material that can prevent poor appearance at the seam portions of the ends of the cover pieces.

[0010] In order to solve the above-mentioned problems, the seat covering material of the present invention is a seat covering material that constitutes the surface of a seat, the covering material having two cover pieces each including a first layer and a second layer laminated on the back surface of the first layer, the two cover pieces being sewn together at a seam, and each of the two cover pieces having a folded end, the folded end having a seam allowance that constitutes the end side of the folded end relative to the seam, and a base portion that constitutes the base side of the folded end relative to the seam, and the seam allowance of the two cover pieces is The second layer is folded back from a base portion of the outer skin piece so that the second layer is located inside the first layer and overlaps with the base portion with the ends of the seam allowance facing in opposite directions, the ends of the seam allowance are overlapped with the second layer of the base portion, the thickness of the second layer of the seam allowance is set to be thinner than the thickness of the second layer of a central portion of the outer skin piece that is closer to the center than the base portion, and the thickness of the second layer of the base portion is set to be thinner than the thickness of the central portion at least within a predetermined first width range from the seam allowance.

[0011] 1 is a cross-sectional view showing the overall configuration of a seat upholstery material according to a first embodiment of the present invention; FIG. 2 is an explanatory cross-sectional view showing a process of sewing two upholstery pieces of the seat upholstery material of FIG. 1 together using a sewing machine; FIG. 3 is a cross-sectional view showing the upholstery pieces of FIG. 1 in a state before being sewn together; FIG. 4 is an explanatory cross-sectional view explaining that the seam margin end of the upholstery piece of FIG. 1 abuts against the second layer in the central portion; FIG. 5 is a cross-sectional view of a upholstery piece according to a modified example of the first embodiment of the present invention, showing an example in which the thickness of the second layer in a portion overlapping the seam margin end at the base of the folded-back end of the upholstery piece is the same as the thickness of the second layer in the central portion; FIG. 6 is a cross-sectional view of a upholstery piece according to another modified example of the first embodiment of the present invention, showing an example in which the second layer in the vicinity of the seam margin end has been removed; FIG. 7 is a cross-sectional view of a upholstery piece according to yet another modified example of the first embodiment of the present invention, showing an example in which the second layer in the vicinity of the seam margin end has been removed and the thickness of the second layer in a portion overlapping the seam margin end at the base of the upholstery piece end is the same as the thickness of the second layer in the central portion. 12A and 12B are cross-sectional views showing a structure in which the second layer of each of the seam allowances at the folded end and the base portion of an upholstery piece according to a second embodiment of the present invention is configured with an inclined portion that becomes thinner toward the seam allowance end, (a) is a cross-sectional view showing the state before folding back the seam allowance, and (b) is a cross-sectional view showing the state after folding back the seam allowance. 12B is a cross-sectional view showing a structure in which the second layer of the seam allowance at the folded end of an upholstery piece according to a third embodiment of the present invention is configured with an inclined portion and the second layer of the base portion is configured with a flat portion. 12C is a perspective view showing the overall structure of an automobile seat having an upholstery formed by sewing together four upholstery pieces shown in FIG. 3 according to a fourth embodiment of the present invention. 12D is a plan view showing the state before sewing of the four upholstery pieces that make up the upholstery of FIG. 10, as viewed from the back side. 12E is a process explanatory view showing the process of sewing two upholstery pieces aligned in the front-rear direction of the seat shown in FIG. 10 together with a first seam extending in the vertical direction, showing the state in which the sewn set of two upper upholstery pieces and the set of two lower upholstery pieces are each unfolded. 12F is a cross-sectional view taken along A1-A1 of FIG. 12C. 14 is a process explanatory view showing the state in which the set of two upper skin pieces and the set of two lower skin pieces sewn together in Fig. 12 are unfolded after being sewn together by a second seam extending in the front-rear direction.Fig. 16 is a plan view, seen from the back side, of the four sewn up skin pieces in Fig. 14, of which two up-down aligned skin pieces are further sewn together with a third seam (stitch) extending in the up-down direction. Fig. 16 is a cross-sectional view taken along A2-A2 in Fig. 16. Fig. 16 is a cross-sectional view taken along B2-B2 in Fig. 16. Fig. 16 is a plan view, seen from the front side, of the four sewn up skin pieces in Fig. 16, of which two up-down aligned skin pieces are sewn together with a third seam (stitch) extending in the up-down direction.

[0012] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A seat covering material according to an embodiment of the present invention will be described in detail below with reference to the drawings.

[0013] First Embodiment As shown in FIG. 1, a seat covering material 1 is a covering material that forms the surface of a seat such as a vehicle seat.

[0014] The skin material 1 has at least two skin pieces 2 connected to each other by stitching.

[0015] 1 to 4, the skin piece 2 has a first layer 3 and a second layer 4 that is laminated on the back surface of the first layer 3 and has more cushioning properties than the first layer 3. The skin piece 2 is configured by laminating the first layer 3 and the second layer 4.

[0016] For example, natural leather, synthetic leather, or a synthetic resin sheet material is used for the first layer 3. For example, foamed resin, foamed rubber, a soft resin material, or a net material is used for the second layer 4.

[0017] When viewed in plan, each skin piece 2 has a central portion 5 that forms the center of the skin piece 2, and folded end portions 6 that are folded around the central portion 5 so that the first layer 3 faces outward.

[0018] In this embodiment, as shown in FIGS. 1 and 4, the facing folded end portions 6 of the two skin pieces 2 are sewn together by a seam 7 with the first layers 3 abutting against each other.

[0019] 2, the two unfolded folded end portions 6 are first overlapped with the first layers 3 abutting each other, resulting in a stack of the second layer 4, the first layer 3, the first layer 3, and the second layer 4. Then, with the presser plate M1 of the sewing machine M in contact with the surface of the second layer 4, the uppermost layer at the end portions 6 (specifically, the second layer 4a at the seam allowance 8 and the second layer 4b at the base portion 9, which will be described later), the two end portions 6 are sewn together using the sewing machine M to form the sewn portion 7.

[0020] Each of the folded ends 6 has a seam allowance 8 that forms a portion of the folded end 6 closer to the tip (end) side than the seam 7, and a base portion 9 that forms a portion of the folded end 6 closer to the base than the seam 7. In this embodiment, the width L1 of the seam allowance 8 and the width L2 of the base portion 9 are set to the same width. Furthermore, the second layer 4a of the seam allowance 8 and the second layer 4b of the base portion 9 are formed as flat portions having a uniform thickness, which makes it easy to press the second layers 4a, 4b with the presser plate M1 of the sewing machine M during sewing.

[0021] As shown in Figures 1 and 4, the seam allowances 8 of the two skin pieces 2 are folded back from the stitched portion 7 so that the second layer 4 is located inside the first layer 3 and the ends of the seam allowances 8 (hereinafter referred to as seam allowance ends 10) face in opposite directions.

[0022] The seam allowance end 10 is overlapped with the second layer 4b of the root portion 9 at the folded end 6. In other words, the root portion 9 is formed by the portion of the folded end 6 that overlaps with the seam allowance end 10.

[0023] As shown in Figure 3, the thickness δ1 of the second layer 4a of the seam allowance 8 is set to be thinner than the thickness δ3 of the second layer 4c of the central portion 5, which is the portion closer to the center than the base portion 9 of the skin piece 2. Tools used for thinning include, for example, a skiving machine, a peeler, and a file.

[0024] The thickness δ2 of the second layer 4b of the root portion 9 is set to be thinner than the thickness δ3 of the central portion 5 at least in the range from the seam allowance 8 to a predetermined first width. In the first embodiment, the predetermined first width is set to the entire width L2 of the root portion 9 in Fig. 3. Therefore, the thickness δ2 of the second layer 4b of the root portion 9 is set to be thinner than the thickness δ3 of the central portion 5 over the entire width L2 of the root portion 9.

[0025] When considering the continuity with the second layer 4c at the central portion 5 of the skin piece 2, it is preferable that the predetermined first width is equal to or slightly smaller than the width L2 of the seam allowance 8, as described above, and that the seam allowance end portion 10 abuts against or is close to the second layer 4c at the central portion 5 of the skin piece 2 (specifically, the side surface 4c1 near the seam allowance end portion 10 in Figure 4).

[0026] Furthermore, in order to eliminate undulations between the overlapping portion of the second layer 4 a of the seam allowance 8 and the second layer 4 b of the base portion 9 and the second layer 4 c of the central portion 5, the thickness δ1 of the second layer 4 a of the seam allowance 8 and the thickness δ2 of the second layer 4 b of the base portion 9 are set so that the sum δ1 + δ2 of the thicknesses of these second layers 4 a, 4 b is approximately equal to the thickness δ3 of the second layer 4 c of the central portion 5 of the skin piece 2.

[0027] (Features of the First Embodiment) (1) In the seat cover material 1 according to the first embodiment described above, it is possible to prevent poor appearance of the cover material 1 due to direct contact of the first layer 3 at the folded-back seam allowance end 10 of the cover piece 2 with the first layer 3 of the cover piece 2 in a portion other than the seam allowance 8.

[0028] That is, the seam allowance 8 at the folded end 6 of each of the two outer skin pieces 2 is folded back starting from the sewn portion 7 so that the second layer 4 is located inside the first layer 3 and the seam allowance ends 10 face in opposite directions. The seam allowance end 10 is overlapped with the second layer 4b at the base portion 9 of the folded end 6. Therefore, at least the second layer 4b of the base portion 9 is interposed between the first layer 3 at the seam allowance end 10 and the first layer 3 at the base portion 9 (in the first embodiment, both the second layer 4a of the seam allowance 8 and the second layer 4b of the base portion 9 are interposed), so the first layer 3 at the seam allowance end 10 does not directly contact the first layer 3 at the base portion 9. Therefore, the outline of the first layer 3 at the seam allowance end 10 does not appear on the first layer 3 at the base portion 9.

[0029] Furthermore, the thickness δ1 of the second layer 4a of the seam allowance 8 is set to be thinner than the thickness δ3 of the second layer 4c of the central portion 5 of the skin piece 2, and the thickness δ2 of the second layer 4b of the root portion 9 is set to be thinner than the thickness δ3 of the central portion 5, at least within a range of a predetermined first width (the width L2 of the entire root portion 9 in the first embodiment) from the seam allowance 8. Therefore, an increase in the thickness of the overlapped seam allowance 8 and root portion 9 can be suppressed.

[0030] With the above-described configuration, the skin material 1 of the first embodiment can prevent poor appearance at the stitched portions at the ends of the skin pieces 2.

[0031] (2) In the skin material 1 of the first embodiment, the predetermined first width is equal to or slightly smaller than the width L1 of the seam allowance 8. The seam allowance end 10 abuts against or is close to the second layer 4c of the central portion 5 of the skin piece 2 (specifically, the side surface 4c1 close to the seam allowance end 10 in Fig. 4).

[0032] As a result, the overlapping portions of the thinner second layer 4 at the seam allowance 8 and base portion 9 and the second layer 4 at the center portion 5 of the skin piece 2 are continuous with each other at substantially the same thickness, so that defects due to undulations at the folded end portion 6 of the skin piece 2 can be suppressed.

[0033] (3) Furthermore, in the upholstery material 1 of the first embodiment, the second layer 4a of the seam allowance 8 and the second layer 4b of the base 9 are formed as flat portions with uniform thickness. Therefore, during the sewing operation, the second layer 4a of the seam allowance 8 and the second layer 4b of the base 9, which are formed as flat portions, can be stably pressed down by the presser plate M1 of the sewing machine M. As a result, the seam 7 can be stably formed, improving the workability of the sewing operation of the upholstery material 1.

[0034] (4) In the upholstery material 1 of the first embodiment, the thickness δ1 of the second layer 4a at the seam allowance 8 and the thickness δ2 of the second layer 4b at the base portion 9 are set so that the sum δ1 + δ2 of the thicknesses of these second layers 4a, 4b is approximately equal to the thickness δ3 of the second layer 4c at the center portion 5 of the upholstery piece 2. This makes it possible to make the thickness of the second layer 4 substantially uniform near the folded end 6, i.e., at the folded end 6 and the center portion 5 of the upholstery piece 2, and effectively suppresses defects due to undulations near the folded end 6.

[0035] (Modifications of the First Embodiment) (A) In the first embodiment described above, as shown in Fig. 3, the thickness δ2 of the second layer 4b of the base portion 9 is set to be thinner than the thickness δ3 of the central portion 5 over the entire width L2 of the base portion 9, but the present invention is not limited to this. In the present invention, it is sufficient that the thickness δ2 of the second layer 4b of the base portion 9 is set to be thinner than the thickness δ3 of the central portion 5 at least in the range from the seam allowance 8 to a predetermined first width. Therefore, the thickness δ2 may be thinner not only over the entire width L2 of the base portion 9 but also in the range from the seam allowance 8 to a first width narrower than the entire width L2.

[0036] Therefore, as in the modified example shown in Figure 5, the thickness of the portion 4b1 of the second layer 4b of the base portion 9 closer to the seam allowance 8 may remain thin, while the thickness of the portion 4b2 closer to the central portion 5 may be thick.

[0037] (B) As another modification of the first embodiment, as shown in Fig. 6, the second layer 4a of the seam allowance 8 may be partially removed within a range of a predetermined second width L3 including the seam allowance end 10. In other words, the thickness of the portion of the second layer 4a of the seam allowance 8 within the range of the second width L3 may be zero. The first layer 3 at the seam allowance end 10 shown in Fig. 6 is in direct contact with the second layer 4b of the base portion 9.

[0038] In the modified example shown in Figure 6, the second layer 4a of the seam allowance 8 is partially removed within the range of the second width L3 including the seam allowance end 10, making it possible to further reduce the thickness in the area where the seam allowance end 10 overlaps with the base portion 9.

[0039] (C) As yet another modification of the first embodiment, it may be a combination of the above modifications (A) and (B), i.e., as shown in FIG. 7, the second layer 4a near the seam end 10 is removed within a predetermined range L4, and the thickness of the second layer 4b2 at the base 9 of the folded end 6 that overlaps with the seam end 10 is the same as the thickness of the second layer 4c in the central portion 5.

[0040] In the modified example (C) shown in FIG. 7 , similarly to the modified example (A) shown in FIG. 5 , the thickness of the portion 4 b 2 of the second layer 4 b at the base portion 9 that directly contacts the first layer 3 at the seam allowance end portion 10 is set to be equal to the thickness δ 3 of the second layer 4 c at the central portion 5.

[0041] Therefore, according to the modification shown in FIG. 7, the first layer 3 of the seam allowance end portion 10 from which the second layer 4 has been removed comes into contact with the portion 4b2 of the second layer 4b of the root portion 9, which has a thickness equal to the thickness δ3 of the second layer 4c of the central portion 5, so that it is possible to suppress defects caused by undulations in the overlapping portion of the seam allowance end portion 10 and the root portion 9.

[0042] (Second embodiment) In the first embodiment described above, as shown in FIG. 3, the second layer 4a of the seam allowance 8 and the second layer 4b of the base portion 9 are configured as flat portions having a uniform thickness, but the present invention is not limited to this, and other configurations may be used as long as they are thinner than the second layer 4c of the central portion 5 of the skin piece 2.

[0043] From this perspective, in the second embodiment, as shown in Fig. 8(a), the second layer 4a of the seam allowance 8 and the second layer 4b of the base portion 9 are configured with inclined portions that become thinner toward the seam allowance end portion 10. Therefore, these second layers 4a, 4b have inclined surfaces 4a1, 4b1 that are continuous with each other and inclined at the same angle.

[0044] 8(b) (i.e., when the inclined surfaces 4a1, 4b1 are overlapped), the overlapping portion of the second layer 4a of the seam allowance 8 and the second layer 4b of the base portion 9 is flat and continues with the flat second layer 4c of the central portion 5. This makes it possible to effectively suppress defects caused by undulations at the folded end portion 6 of the skin piece 2.

[0045] (Third embodiment) In the third embodiment, as shown in Fig. 9, the second layer 4a of the seam allowance 8 has an inclined portion whose thickness decreases toward the seam allowance end 10. The second layer 4a has an inclined surface 4a1. It is sufficient that the second layer 4a has an inclined portion at least in the portion close to the seam allowance end 10, but the entire second layer 4a may be composed of an inclined portion as shown in Fig. 9. On the other hand, the second layer 4b of the base portion 9 is composed of a flat portion having a uniform thickness.

[0046] 9 , the second layer 4a of the seam allowance 8 has an inclined portion that becomes thinner toward the seam allowance end 10, making it easy to fold the seam allowance 8 along the sewn portion 7, improving workability in the manufacturing process of the upholstery material 1. Moreover, the second layer 4b of the root portion 9 is formed as a flat portion with a uniform thickness, making it possible to ensure the thickness at the folded end 6 where the seam allowance 8 and the root portion 9 are overlapped. This makes it possible to make the thickness substantially uniform, effectively preventing problems due to undulations near the folded end 6.

[0047] When the seam allowance 8 is simply folded back, a gap remains between the second layer 4a consisting of the inclined portion and the second layer 4b consisting of the flat portion. However, by stitching the seam allowance 8 with the stitch described below (third stitching portion 78 in Figures 16 to 19), the second layers 4a and 4b are compressed, and this gap disappears.

[0048] (Fourth embodiment) Next, as a fourth embodiment of the present invention, a vehicle seat 51 (hereinafter referred to as seat 51) provided with a seat cover material 56 (hereinafter referred to as cover material 56) according to one embodiment of the present invention will be described with reference to Figures 10 to 19.

[0049] The seat 51 shown in FIG. 10 includes a cover material 56 that forms the surface of the seat 51, and an airbag device 69 (hereinafter referred to as airbag 69) that protects an occupant of the seat 51 from impact in the event of a vehicle collision.

[0050] The specific configuration of the seat 51 is as follows: The seat 51 includes a seat cushion 52 against which the buttocks of a seated person can come into contact, a seat back 53 against which the back of the seated person can come into contact, and an airbag 69.

[0051] The seat back 53 includes a top panel portion 70 that faces the front of the vehicle X1 and against which the back of a seated occupant can abut, a pair of bolster portions 54 that are arranged adjacent to both sides of the top panel portion 70 in the vehicle width direction Y, a pair of shoulder portions 55 that are arranged above the pair of bolster portions 54, and an upholstery material 56 that forms the surfaces of the bolster portions 54 and the shoulder portions 55.

[0052] The bolster portion 54 is a vertically long cushion-like portion that protrudes forward and to the side of the seat back 53 near the sides of the seated occupant's body. The bolster portion 54 in this embodiment is composed of a first skin piece 61 and a second skin piece 62 of a skin material 56 (described below), a cushion pad (not shown) covered by the first skin piece 61 and the second skin piece 62, and a frame (not shown) that supports the cushion pad.

[0053] The shoulder portions 55 have portions that protrude forward and to the sides near the shoulders of the seated occupant. In this embodiment, the pair of shoulder portions 55 extend in the width direction Y and are integrated, but they may also be separated from each other.

[0054] The surface portions of the bolster portion 54 and shoulder portion 55 on the outer side in the vehicle width direction (right side in FIG. 10 ), where the airbag 69 is housed, are made of a skin material 56 formed by sewing together a plurality of skin pieces. The airbag 69 is disposed on the inside of the skin material 56, along a third seam 78 (stitch) extending in the up-down direction Z. The third seam 78 will be described later.

[0055] The skin material 56 includes four skin pieces 61 to 64. Specifically, the skin material 56 includes a first skin piece 61 disposed adjacent to the top panel 70 in the bolster portion 54 (i.e., on the top panel side), a second skin piece 62 disposed on the bolster portion 54 on the lining side farther from the top panel 70 than the first skin piece 61 (i.e., on the side that forms the side of the seat back 53), a third skin piece 63 disposed above the first skin piece 61 in the shoulder portion 55 (i.e., on the top panel side), and a fourth skin piece 64 disposed above the second skin piece 62 in the shoulder portion 55 (i.e., on the lining side).

[0056] Thus, the four outer skin pieces 61-64 are arranged two by two in each of the vertical direction Z and the front-to-back direction X of the sheet 51. Each outer skin piece 61-64 has an outer skin piece end portion 80 that faces the other outer skin pieces 61-64 in the vertical direction Z and the front-to-back direction X, and a central portion 84 that is the remaining portion. The opposing outer skin piece end portions 80 are stacked with the fronts facing outwards (i.e., with the first layers 81 butted together), and then the seams 71, 75 are sewn together. The first layers 81 of the outer skin pieces are then opened flat from the seams. At this time, the seams 72, 76 are folded back from the seams 71, 75 so that the seam end portions face in opposite directions. Note that Figures 11, 12, 14, and 16 below show the back sides of the outer skin pieces 61-64, from which the first seam allowance 72 and second seam allowance 76, described below, are visible.

[0057] As in the first embodiment, each of the skin pieces 61 to 64 has a structure in which a first layer 81 and a second layer 82 are laminated together, as shown in Fig. 13 . A skin piece end portion 80 extending in the up-down direction Z of each of the skin pieces 61 to 64 is composed of a first seam allowance 72 and a first base portion 73. The thicknesses of the second layer 82a of the first seam allowance 72 and the second layer 82b of the first base portion 73 are thinner than the thicknesses of the second layer 82c of the central portion 84 of each of the skin pieces 61 to 64. Similarly to the skin piece end portions 80 extending in the up-down direction Z, the second layer of each of the skin pieces 61 to 64 is also thinner than the second layer 82c of the central portion 84.

[0058] The stitching structure of the four skin pieces 61 to 64 using three stitches, namely, the first stitch 71, the second stitch 75, and the third stitch 78, will be described below in order.

[0059] As shown in Figures 12 and 13, the skin piece ends 80 extending in the front-to-rear direction X of the two skin pieces 61, 63 (and skin pieces 62, 64) arranged in the up-down direction Z are sewn together by a first stitching portion 71 which is a stitching portion extending in the front-to-rear direction X, and two first seam allowances 72 which are seam allowances extending in the front-to-rear direction X are formed.

[0060] The two first seams 72 are folded back so that the seam end portions 72a face in opposite directions, starting from the first sewn portion 71. As a result, the first seams 72 and the first base portion 73 are overlapped, but because the second layers 82a and 82b are thin, it is possible to reduce the thickness of the overlapping portions of the first seams 72 and the first base portion 73.

[0061] 11 are sewn together by a second seam 75 extending in the vertical direction Z, as shown in FIG. 14, and two second seam allowances 76 extending in the vertical direction Z are formed. Similarly to the first seam 72, the second seam allowances 76 are folded back from the second seam 75 as a starting point so that the seam allowance ends face in opposite directions. The second seam allowance 76 thus formed, extending in the vertical direction Z, and the second root portion 77 (see FIG. 15) overlapping it also have thin second layers 82, making it possible to reduce the thickness of the overlapping portions of the second seam allowance 76 and the second root portion 77.

[0062] 14 and 15, at a portion C where the first seam allowance 72 extending in the front-rear direction X and the second seam allowance 76 extending in the up-down direction Z intersect, the overlapping portion of the first seam allowance 72 and the first root portion 73 is inside the overlapping portion of the second seam allowance 76 and the second root portion 77. As a result, at the intersecting portion C, a structure in which four thin second layers 82 are stacked is formed, making it possible to reduce the overall thickness at the intersecting portion C.

[0063] 16 to 19, at the ends of at least two of the four outer skin pieces 61 to 64, namely, the outer skin pieces 61 and 63, which are arranged in the up-down direction Z, a third seam 78 (stitch) extending in the up-down direction Z is used to sew together the second seam allowance 76 and the second root portion 77 (see FIG. 17, which shows the A2-A2 cross section of FIG. 16). At the same time, the third seam 78 sews together the first seam allowance 72 and the first root portion 73 in an overlapping state with the second seam allowance 76 and the second root portion 77. Specifically, as shown in FIG. 18, at an intersection C of the first seam allowance 72 and the second seam allowance 76, the overlapping portion of the first seam allowance 72 and the first root portion 73 is sewn together by the third seam 78 in a state where it is inside the overlapping portion of the second seam allowance 76 and the second root portion 77. At the intersection C, the thinned second layer 82 is laminated in four layers, and the overall thickness at the intersection C is suppressed, so that when the intersection C is sewn at the third seam 78, the swelling of the seam allowance is suppressed and the sewing line is less likely to meander.

[0064] In the configuration of the sheet 51 described above, as shown in Fig. 17 , in the overlapping portion of the second seam allowance 76 and the second root portion 77 extending in the up-down direction Z, the second layers 82a, 82b of the second seam allowance 76 and the second root portion 77 are thinner than the second layer 82c of the central portion 84 of the skin pieces 61 to 64. Also, as shown in Fig. 18 , in the overlapping portion of the first seam allowance 72 and the first root portion 73 extending in the front-rear direction X, the second layers 82 of the first seam allowance 72 and the first root portion 73 are thinner than the second layer 82 of the central portion 84 of the skin pieces 61 to 64.

[0065] Therefore, at the up-down direction Z-extending up-down direction Z of two up-down direction Z-aligned up-down direction Z ...

[0066] Furthermore, since the airbag 69 is disposed inside the upholstery material 56 and along the third seam 78, when the airbag 69 is deployed, the third seam 78 extending in the up-down direction Z maintains the state in which the two upholstery pieces 61, 63 aligned in the up-down direction Z are connected, while the first seam 71 extending in the up-down direction Z breaks first, thereby reliably forming an opening between the two upholstery pieces 61, 62 (and upholstery pieces 63, 64) aligned in the front-rear direction X that allows the airbag 69 to inflate outside the seat 51. This makes it possible to maintain the deployment function of the airbag 69.

[0067] As described above, the seat 51 can improve its appearance while maintaining the performance of the deployment function of the airbag 69.

[0068] Furthermore, in the configuration of the sheet 51 described above, the second layer 82 of the skin piece end 80 sewn together at the first seam 71, the second seam 75, and the third seam 78 is thin, making it easier for the worker to press it down with their hands, facilitating the sewing operation.

[0069] <Summary of the embodiment> The above embodiment can be summarized as follows.

[0070] The seat covering material of this embodiment is a seat covering material that forms the surface of a seat, and the covering material has two cover pieces that include a first layer and a second layer laminated on the back surface of the first layer, and the two cover pieces are sewn together at a seam, and each of the two cover pieces has a folded end, and the folded end has a seam allowance that forms an end side of the folded end relative to the seam, and a base portion that forms a base side of the folded end relative to the seam, and the seam allowance of the two cover pieces is The second layer is located inside the first layer and overlaps with the root portion with the ends of the seam allowance folded back so that they face in opposite directions, the ends of the seam allowance are overlapped with the second layer of the root portion, the thickness of the second layer of the seam allowance is set to be thinner than the thickness of the second layer of the central portion, which is the portion of the skin piece closer to the center than the root portion, and the thickness of the second layer of the root portion is set to be thinner than the thickness of the central portion, at least within a predetermined first width range from the seam allowance.

[0071] This configuration can prevent poor appearance of the upholstery material due to direct contact between the first layer at the end of the folded seam allowance in the upholstery piece and the first layer in the portion of the upholstery piece other than the seam allowance.

[0072] That is, the seam allowances at the folded ends of the two outer skin pieces are folded back starting from the seam, with the second layer positioned more inward than the first layer, and the ends of the seam allowance facing in opposite directions. The ends of the seam allowance are then overlapped with the second layer at the base of the end of the outer skin piece. Therefore, at least the second layer at the base is interposed between the first layer at the seam allowance end and the first layer at the base, so the first layer at the seam allowance end does not directly contact the first layer at the base. As a result, the outline of the first layer at the seam allowance end does not appear on the first layer at the base.

[0073] Furthermore, the thickness of the second layer in the seam allowance is set to be thinner than the thickness of the second layer in the central portion of the skin piece, and the thickness of the second layer in the base portion is set to be thinner than the thickness of the central portion at least within a predetermined first width from the seam allowance, thereby making it possible to prevent an increase in the thickness of the overlapped seam allowance and base portion.

[0074] This makes it possible to prevent poor appearance of the skin material at the seam portions of the ends of the skin pieces.

[0075] In the above-described seat covering material, it is preferable that the predetermined first width is equal to or slightly smaller than the width of the seam allowance, and that the end of the seam allowance abuts or is adjacent to the second layer of the central portion of the cover piece.

[0076] As a result, the overlapping portions of the thinner second layers at the seam allowance and base are substantially continuous with the second layer at the center of the skin piece, making it possible to suppress defects caused by unevenness at the ends of the skin piece.

[0077] In the above-described seat covering material, it is preferable that the second layer of the seam allowance is partially removed within a range of a predetermined second width including the end of the seam allowance, and the first layer at the end of the seam allowance is in direct contact with the second layer of the base portion.

[0078] With this configuration, the second layer of the seam allowance is partially removed in the range of the second width including the seam allowance end, making it possible to further reduce the thickness in the area where the seam allowance end and the base portion overlap.

[0079] In the above-described seat covering material, it is preferable that the thickness of the second layer in the base portion that directly contacts the first layer at the end of the seam allowance is set to be equal to the thickness of the second layer in the central portion.

[0080] With this configuration, the first layer at the end of the seam allowance where the second layer has been removed comes into contact with a portion of the second layer at the base that is equal in thickness to the second layer at the center, thereby making it possible to suppress defects caused by unevenness at the area where the end of the seam allowance and the base overlap.

[0081] In the above-mentioned seat covering material, the second layer of the seam allowance and the base portion is preferably formed of a flat portion having a uniform thickness.

[0082] With the above configuration, the flat seam allowance and the second layer of the base can be stably pressed down with the presser plate of the sewing machine during sewing, which results in stable formation of the seam and improves workability in sewing the cover material.

[0083] In the above-described seat covering material, it is preferable that the thicknesses of the second layers at the seam allowance and the base portion are set so that the sum of the thicknesses of these second layers is equal to the thickness of the second layer at the central portion of the covering piece.

[0084] With this configuration, the overlapping portion of the second layer of the seam allowance and the second layer of the base at the end of the skin piece and the second layer at the center of the skin piece have the same thickness, so it is possible to make the thickness of the second layer substantially uniform near the end of the skin piece, and to effectively suppress defects due to undulations near the end of the skin piece.

[0085] In the above-described seat covering material, the second layer of each of the seam allowance and the base portion is preferably configured with an inclined portion that becomes thinner toward the end of the seam allowance.

[0086] With this configuration, the thickness of the second layers of the seam allowance and the base portion decreases toward the end of the seam allowance, so that when the seam allowance is folded back toward the base portion, the overlapping portion of the second layer of the seam allowance and the second layer of the base portion becomes flat, thereby effectively suppressing defects caused by undulations at the end of the skin piece.

[0087] In the above-described seat covering material, it is preferable that the second layer of the seam allowance has an inclined portion whose thickness decreases toward the end of the seam allowance, and the second layer of the base portion is composed of a flat portion having a uniform thickness.

[0088] With this configuration, the second layer of the seam allowance has an inclined portion that becomes thinner toward the end of the seam allowance, making it easier to fold the seam allowance along the sewn portion, improving workability in manufacturing the upholstery material. Moreover, because the second layer of the base portion is composed of a flat portion with a uniform thickness, it is possible to ensure the thickness of the folded end of the upholstery piece where the seam allowance and base portion are overlapped. This makes it possible to make the thickness substantially uniform, effectively preventing problems caused by undulations near the folded end.

[0089] The vehicle seat of this embodiment is a vehicle seat including the above-mentioned seat upholstery material and an airbag, wherein the seat upholstery material has four of the upholstery pieces, and the four upholstery pieces are arranged so that two pieces are lined up in each of the vertical and longitudinal directions of the seat, and the ends of the two upholstery pieces lined up in the vertical direction are sewn together by a first seam that is the seam that extends in the longitudinal direction with the first layers abutting against each other, and two first seams that are the seam allowances that extend in the longitudinal direction are formed, and the ends of the two upholstery pieces lined up in the longitudinal direction are sewn together by a second seam that is the seam that extends in the vertical direction with the first layers abutting against each other, and two second seams that are the seam allowances that extend in the vertical direction are formed, and the four upholstery pieces are arranged in the vertical direction, and at the ends of at least two of the four upholstery pieces, the first seam allowances and the first root portion are sewn together by a single third seam extending in the vertical direction, and the second seam allowances and the second root portion are sewn together in a state where they are overlapped with the first seam allowances and the first root portion; and the airbag is disposed inside the seat upholstery material and in a position along the third seam.

[0090] According to this configuration, in the overlapping portions of the first seam allowance and the first root portion extending in the front-rear direction, the second layers of the first seam allowance and the first root portion are thinner than the second layers in the central portion of the upholstery piece. Similarly, in the overlapping portions of the second seam allowance and the second root portion extending in the up-down direction, the second layers of the second seam allowance and the second root portion are thinner than the second layers in the central portion of the upholstery piece. Therefore, at the ends of two of the four up-down skin pieces, a single third seam (stitch) extending in the up-down direction sews together the two thinned portions formed by the second seam allowance and the second root portion, and the second seam allowance and the second root portion are sewn together while overlapping the first seam allowance and the first root portion, i.e., the overlapping portions of the four thinned second layers are sewn together. This prevents distortion (meandering) of the third seam. This prevents poor seat appearance.

[0091] Furthermore, since the airbag is positioned inside the seat upholstery material and along the third seam, when the airbag deploys, the third seam extending in the vertical direction maintains the connection between the two up-and-down lined upholstery pieces, while the first seam extending in the vertical direction breaks first, thereby reliably forming an opening between the two up-and-down lined upholstery pieces that allows the airbag to inflate outside the seat, thereby maintaining the airbag's deployment function.

[0092] As described above, the seat covering material and vehicle seat of this embodiment can prevent poor appearance at the seam portions of the ends of the cover pieces.

Claims

1. A sheet covering material that forms the surface of a sheet, the covering material having two sheet pieces comprising a first layer and a second layer laminated on the back surface of the first layer, the two sheet pieces being sewn together at a seam, and each of the two sheet pieces having a folded end, the folded end having a seam allowance that forms the end side of the folded end relative to the seam, and a base portion that forms the base side of the folded end relative to the seam, the seam allowances of the two sheet pieces overlap with the base portion in a state where the second layer is located inside the first layer and the ends of the seam allowance face in opposite directions, the end of the seam allowance overlaps with the second layer at the base portion, the thickness of the second layer at the seam allowance is set to be thinner than the thickness of the second layer at a central portion of the sheet piece that is closer to the center than the base portion, a thickness of the second layer at the base portion is set to be thinner than a thickness of the central portion at least within a range of a predetermined first width from the seam allowance.

2. A seat covering material according to claim 1, wherein the predetermined first width is equal to or slightly smaller than the width of the seam allowance, and the end of the seam allowance abuts or is adjacent to the second layer in the central portion of the cover piece.

3. A seat covering material according to claim 2, wherein the second layer of the seam allowance is partially removed within a range of a predetermined second width including the end of the seam allowance, and the first layer at the end of the seam allowance is in direct contact with the second layer at the base portion.

4. A seat covering material according to claim 3, wherein the thickness of the second layer at the base portion that directly contacts the first layer at the end of the seam allowance is set to be equal to the thickness of the second layer at the central portion.

5. A seat covering material according to claim 1 or 2, characterized in that the second layer of the seam allowance and the base portion is made up of flat portions having a uniform thickness.

6. A seat covering material as set forth in claim 5, wherein the thicknesses of the second layers at the seam allowance and the base portion are set so that the sum of the thicknesses of these second layers is equal to the thickness of the second layer at the center portion of the cover piece.

7. A seat covering material as claimed in claim 1 or 2, characterized in that the second layer of each of the seam allowance and the base portion is made up of an inclined portion whose thickness decreases toward the end of the seam allowance.

8. A seat covering material as claimed in claim 1 or 2, characterized in that the second layer of the seam allowance has an inclined portion whose thickness decreases toward the end of the seam allowance, and the second layer of the base portion is composed of a flat portion having a uniform thickness.

9. A vehicle seat comprising a seat covering material according to claim 1 or 2 and an airbag, wherein the seat covering material has four of the covering pieces, the four covering pieces are arranged so that two pieces are lined up in each of the vertical and longitudinal directions of the seat, the ends of the two covering pieces lined up in the vertical direction are sewn together by a first seam that is the seam that extends in the longitudinal direction with the first layers abutting against each other, and two first seams that are the seam allowances that extend in the longitudinal direction are formed, the ends of the two covering pieces lined up in the longitudinal direction are sewn together by a second seam that is the seam that extends in the vertical direction with the first layers abutting against each other, and two second seams that are the seam allowances that extend in the vertical direction are formed, and the two first seams are folded back from the first seam as a starting point so that the ends of the first seams face in opposite directions and overlap a first base portion, the two second seams are folded back starting from the second sewn portion so that ends of the second seams face in opposite directions and overlap the second root portion; at ends of at least two of the four upholstery pieces that are aligned in the vertical direction, the first seam and the first root portion are sewn together by a single third seam extending in the vertical direction, and the second seam and the second root portion are sewn together in a state where they overlap the first seam and the first root portion; and the airbag is disposed inside the seat upholstery material and in a position along the third seam.

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