Seat back

Abstract

A seat back (2) is provided with: a seat cushion body (20) that elastically supports a seated person; a backrest frame that supports the cushion body (20) from the seat back side; and a waist plate (14) which is attached to the backrest frame and which is capable of adjusting the position of the seat in the front-rear direction, said position supporting the seat cushion body (20) from the seat back side. The cushion body (20) has a main cushion pad as a cushion part, and a main cushion resin member (21C) fixed to a pad back surface, which is a surface on the seat back side of the main cushion pad. The main pad resin member (21C) has an engagement section (C13) that is directly engaged with the waist plate (14) so as to be able to follow the movement of the waist plate (14) toward the rear of the seat.

Description

Technical Field

[0001] The present invention relates to a seat backrest. More specifically, it relates to a seat backrest having a seat cushion body that elastically supports a seated person and a seat frame that supports the seat cushion body from the back side of the seat. Background Art

[0002] The vehicle seat disclosed in Japanese Unexamined Patent Application Publication No. 2020-33005 (Patent Document 5) has a seat cushion body composed of a seat cushion and a seat cover. Moreover, the seat cushion body is divided into three parts in the seat width direction. Specifically, the seat cushion body is configured to be divided into a main cushion plate constituting the central part in the seat width direction and side cushion plates constituting the side surface parts in the seat width direction. The main cushion plate and each side cushion plate are separately assembled and fixed to the seat frame. Summary of the Invention Problems to be Solved by the Invention

[0003] In the structure described in Patent Document 5, when a lumbar plate for adjusting the support position of the lumbar region of the seated person in the front-rear direction is provided on the seat backrest, there is a problem that it is difficult for the main cushion plate to follow the movement of the lumbar plate returning from the extended position. It is considered that the reason is that since the main cushion plate is separated from each side cushion plate, it is difficult to receive the action of the restoring force from each side cushion plate. However, such a problem may also occur in a structure in which the seat cushion body is not divided. Therefore, conventionally, a seat backrest that can appropriately follow the front-rear movement of the lumbar plate has been required. Means for Solving the Problems

[0004] One aspect of the present disclosure is a seat backrest having a seat cushion body that elastically supports a seated person and a seat frame that supports the seat cushion body from the back side of the seat. The seat backrest has a lumbar plate that is mounted on the seat frame and can adjust the position of the seat in the front-rear direction for supporting the seat cushion body from the back side of the seat. The seat cushion body has a seat cushion as a seat cushion part and a support member fixed to the back surface of the seat cushion, which is the back side of the seat cushion. The support member has an engaging portion that directly engages with the lumbar plate in a manner that can follow the movement of the lumbar plate toward the rear of the seat.

[0005] Therefore, by moving the lumbar plate toward the front of the seat, the support position of the lumbar plate on the seat cushion body can be adjusted toward the front of the seat. In addition, by moving the lumbar plate toward the rear of the seat, the support member of the seat cushion body directly engages with the lumbar plate at the engaging portion, and thus, with such a structure, the seat cushion body can appropriately move toward the rear following the lumbar plate.

[0006] According to other aspects of the present disclosure, the seat cushion body is composed of three divided elements, namely a main cushion plate that forms the central part in the seat width direction and side cushion plates that form both side parts in the seat width direction. The support member is provided on the back surface of the cushion of the main cushion plate that forms the main cushion plate of the seat cushion.

[0007] Therefore, even in the structure where the seat cushion body is divided into the main cushion plate and the side cushion plates, the main cushion plate can appropriately follow the forward and backward movement of the lumbar plate.

[0008] According to other aspects of the present disclosure, the lumbar plate has a pair of hooking portions that protrude outward in the seat width direction at both edges in the seat width direction thereof. The engaging portion of the support member is directly engaged with the lumbar plate by hooking on the surfaces on the seat back side of the pair of hooking portions.

[0009] Therefore, it is possible to embody the structure in which the engaging portion of the support member is directly engaged with the lumbar plate in a manner that functions properly by means of a simple structure of hooking the engaging portion on a pair of hooking portions protruding from both edges in the seat width direction of the lumbar plate.

[0010] According to other aspects of the present disclosure, the lumbar plate adjusts the protruding position by bending bow-shaped forward with respect to the seat frame, and can also adjust the position in the height direction.

[0011] Therefore, with the structure of hooking the engaging portion of the support member on a pair of hooking portions protruding from both edges in the seat width direction of the lumbar plate from the seat back side, it is possible to appropriately allow the bending and height position adjustment of the lumbar plate by the sliding of the abutting surfaces thereof.

[0012] According to other aspects of the present disclosure, the lumbar plate has fin portions that protrude outward in the seat width direction at multiple positions in the height direction at both edges in the seat width direction thereof to expand the support surface. The pair of hooking portions are any one of the multiple fin portions.

[0013] Therefore, with the structure of the fin portions of the lumbar plate that expand the support surface, it is possible to reasonably and appropriately hook the engaging portion of the support member on the lumbar plate. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 A perspective view showing a schematic structure of a seat back according to an embodiment. Figure 2 A front view of the seat back. Figure 3 An exploded perspective view of removing the seat cushion body from the backrest frame. Figure 4 A front view of the backrest frame. Figure 5 It is a rear view of the seat cushion body. Figure 6 It is a perspective view showing the assembled state of the seat cushion body to the backrest frame. Figure 7 It is Figure 2 The sectional view taken along line VII-VII of Figure 8 It is a perspective view showing the state of assembling the resin member of the outer side cushion plate to the side frame. Figure 9 It is Figure 2 The sectional view taken along line IX-IX of Detailed Description of the Invention

[0015] One Embodiment (Schematic Structure of Seat Back 2) Using Figures 1 to 9 The structure of the seat back 2 according to one embodiment of the present disclosure will be described. In the following description, the front-rear, up-down, left-right directions are indicated in each figure. The direction marked "seat" refers to the direction based on the orientation of the seat 1. In the following description, when no specific reference figure is shown, or when there is no corresponding symbol in the reference figure, any one of the figures in Figures 1 to 9 is appropriately referred to.

[0016] As Figure 1 shown, the seat back 2 according to the present embodiment is the backrest of the single-seat chair 1 provided on the floor of the vehicle. The seat 1 is the right seat of the vehicle, and includes a seat back 2 that constitutes the backrest of the occupant, a seat cushion 3 that constitutes the seating portion, and a headrest 4 that constitutes the headrest portion.

[0017] As Figure 2 shown, the seat back 2 has a side airbag device 30 on the right side portion that is the outer side in the vehicle width direction. The side airbag device 30 is a well-known device. When a vehicle collision is detected, the airbag 31 breaks through the seat back 2 and bulges forward of the seat to protect the head and chest of the occupant from the impact of the collision.

[0018] As Figure 3 shown, the seat back 2 has a metal backrest frame 10 that constitutes its skeleton and a seat cushion body 20 that is assembled to the front part of the backrest frame 10 and elastically supports the waist and back of the occupant. In addition, the seat back 2 has a backrest plate 40 that is assembled to the rear part of the backrest frame 10 and covers the back surface of the seat back 2. Here, the backrest frame 10 corresponds to one of the "seat frames".

[0019] As Figure 1As shown, the seat cushion body 20 is composed of three divided elements, namely a main cushion plate 21 that divides the central part in the seat width direction and side cushion plates 22 that form both side parts in the seat width direction. The main cushion plate 21 supports the waist and back of the seated person from the rear.

[0020] Each side cushion plate 22 supports the waist and back of the seated person from the rear and obliquely outward. Each side cushion plate 22 has a front surface that forms the front side surface of the seat. The front surface of the side cushion plate 22 forms a surface shape that stands obliquely forward toward the outside in the seat width direction.

[0021] The main cushion plate 21 and each side cushion plate 22 are respectively assembled to the backrest frame 10 from the front of the seat. Specifically, the main cushion plate 21 and each side cushion plate 22 can be easily attached to and detached from the backrest frame 10 without removing the seat 1 from the state where it is set on the floor.

[0022] (Structure of the seat backrest 2) Hereinafter, the specific structure of each part of the seat backrest 2 will be described. As Figures 3 to 4 shown, the backrest frame 10 has a pair of left and right side frames 11 that extend in the vertical direction along the left and right side portions of the seat backrest 2. In addition, the backrest frame 10 has an upper frame 12 and a lower frame 13. The upper frame 12 is horizontally spanned between the upper end portions of the respective side frames 11. The lower frame 13 is horizontally spanned between the lower end portions of the respective side frames 11.

[0023] The backrest frame 10 also has a planar waist plate 14 that is provided in a spanned state between the upper frame 12 and the lower frame 13. The waist plate 14 is provided in a spanned state between the upper frame 12 and the lower frame 13 via a support spring 15 that is bent into a U shape when viewed from the front.

[0024] The two upper ends of the U shape of the support spring 15 pass through the upper frame 12 from below the seat. In addition, the support spring 15 is assembled to the front portion of the lower frame 13 in a state where the lower side of its U shape is elastically supported from the rear of the seat via a torsion spring (not shown). The waist plate 14 is a resin-made flat plate-like member that is long in the vertical direction.

[0025] The waist plate 14 is assembled to the left and right sides of the U shape of the support spring 15 in such a manner that its upper end and lower end can slide in the vertical direction. The waist plate 14 is configured such that, by a drive unit (not shown) assembled to the backrest frame 10, the upper end and lower end of the waist plate 14 move up and down along the respective sides of the support spring 15.

[0026] By moving the lumbar plate 14 in such a way that the distance between its upper end and lower end approaches, the middle part between the upper end and lower end of the lumbar plate 14 flexes in a bowed shape toward the front of the seat. As a result, the support position of the lower half of the main cushion plate 21 of the seat cushion body 20 (the support position of the lumbar region) is pushed forward toward the front of the seat. Thereby, the support pressure of the main cushion plate 21 on the lumbar region of the seated person is enhanced. In addition, by moving the upper end and lower end of the lumbar plate 14 up and down together, the support position of the lumbar region can be adjusted in the vertical direction.

[0027] Both left and right edge portions of the lumbar plate 14 have a plurality of fin portions 14A that project in a wavy shape toward the left and right (the outer sides in the seat width direction). The lumbar plate 14 has a pair of left and right longitudinal surfaces that extend in a planar shape in the vertical direction along the respective side edges of the U-shaped support spring 15. Each fin portion 14A projects outward in a wavy shape from the outer edge of each longitudinal surface of the lumbar plate 14. Thus, each fin portion 14A expands the wavy support surface in a region outside the respective side edges of the U-shaped support spring 15.

[0028] At the rear edge portion of each side frame 11, a plate-shaped fastening bracket 11A that extends obliquely rearward toward the inside in the seat width direction is welded. Each fastening bracket 11A arranges its front surface (the overlapping surface) facing inward and obliquely forward toward the installation space of the main cushion plate 21. At the seat back side of each side cushion plate 22, a fastening portion C25 that extends from the side cushion plate resin member 22C is provided. The corresponding fastening portion C25 is fastened to the fastening bracket 11A via an insertion-type fastening structure.

[0029] At the outer portion on the lower end side of each side frame 11, a bracket having a circular hole-shaped engaging hole 11B is joined. At the lower part of the side cushion plate resin member 22C on the seat back side of each side cushion plate 22, a fitting clip C24 is installed. The corresponding fitting clip C24 engages with the engaging hole 11B along with a snap fit generated by inserting from the front of the seat.

[0030] At two left and right positions of the upper frame 12, support brackets 12A that extend in a square tube shape in the vertical direction are welded in a state of penetrating in the vertical direction. Each support bracket 12A is inserted and welded to the top plate portion and bottom plate portion of the upper frame 12 in a state of penetrating in the vertical direction. The upper end portion of each support bracket 12A is provided so as to project upward from the top plate portion of the upper frame 12 toward the seat.

[0031] Each support bracket 12A functions as an installation portion for inserting and installing the headrest 4 described above from above the seat to the upper part of the seat back 2. Headrest supports (not shown) are respectively inserted and installed from above the seat into each support bracket 12A. The headrest supports can insert and install a pair of left and right headrest struts (not shown) that hang down from the headrest 4 from above the seat. Figure 1

[0032] At both left and right end portions (shoulder portions) of the upper frame 12, fitting holes 12B are respectively formed by hollowing out the top plate portion so as to penetrate in the vertical direction. An upper end fitting portion C22 is formed at the upper part of the side cushion resin member 22C on the seat back side of the side cushion plate 22. The corresponding upper end fitting portion C22 is fitted into each fitting hole 12B by hooking from above the seat.

[0033] (Structure of the main cushion plate 21) Next, the structures of the main cushion plate 21 and each side cushion plate 22 constituting the seat cushion body 20 will be described. First, the structure of the main cushion plate 21 will be described. As Figure 3 、 Figure 5 and Figure 7 shown, as Figure 3 、 Figure 5 and Figure 7 shown, the main cushion plate 21 has a main cushion plate padding 21A, a main cushion plate cover 21B, and a main cushion plate resin member 21C. The main cushion plate padding 21A forms the seat cushion portion. The main cushion plate cover 21B is made of fabric and covers the main cushion plate padding 21A. The main cushion plate resin member 21C is provided on the back side of the main cushion plate padding 21A, that is, the padding back surface. Here, the main cushion plate padding 21A corresponds to the "seat padding". In addition, the main cushion plate resin member 21C corresponds to the "support member" and the "main cushion plate support member".

[0034] As Figure 5 and Figure 7 shown, the main cushion plate padding 21A is constituted by a polyurethane foam molded body. As Figure 3 shown, the main cushion plate padding 21A is formed in a pad shape covering the upper frame 12 and the lumbar plate 14 from the front of the seat. Specifically, the main cushion plate padding 21A has a shape with an eaves portion covering the top plate portion of the upper frame 12 from above the seat at its upper part.

[0035] At the eaves portion at the upper part of the main cushion plate padding 21A, a pair of left and right rectangular hole-shaped support through holes A11 penetrating in the vertical direction are formed. When the main cushion plate padding 21A covers the top plate portion of the upper frame 12 via the main cushion plate resin member 21C described later at its eaves portion, each support through hole A11 is provided on the top plate portion by passing through the upper end portions of the corresponding support brackets 12A.

[0036] The main cushion plate cover 21B covers the main cushion plate padding 21A from the front of the seat. The peripheral portions of the main cushion plate cover 21B in the up, down, left, and right directions are pulled into the padding back surface of the main cushion plate padding 21A and fixed. Specifically, as Figure 5 shown, the ends of the peripheral portions of the main cushion plate cover 21B pulled into the padding back surface are hooked and fixed to the main cushion plate resin member 21C which is frame-shaped when viewed from the rear and provided on the padding back surface.

[0037] By means of the above-mentioned hanging, the main backing plate cover 21B is disposed on the entire outer surface of the main backing plate gasket 21A. In addition, the main backing plate resin member 21C is fixed in a state of pressing against the back surface of the gasket of the main backing plate gasket 21A by hanging at each end of the main backing plate cover 21B. In the eaves region of the eaves portion of the main backing plate cover 21B covering the main backing plate gasket 21A, square-hole-shaped support through-holes B11 that communicate the respective support through-holes A11 with the outside are formed so as to penetrate in the vertical direction.

[0038] As Figure 7 shown, the middle portion in the vertical direction of the region of the main backing plate cover 21B covering the front surface of the main backing plate gasket 21A is lifted from the front of the seat and is fixed in a hanging groove A12 formed at a corresponding position of the main backing plate gasket 21A. Specifically, a suspension portion B12 is formed on the back surface of the cover of the above-mentioned lifted middle portion of the main backing plate cover 21B. The suspension portion B12 includes a suspension cotton cloth and a suspension thread. The suspension cotton cloth is a tubular cotton cloth that is sewn so as to extend in the seat width direction along the middle portion. The suspension thread passes through the suspension cotton cloth.

[0039] The suspension portion B12 is pulled in from the front of the seat and is formed in the hanging groove A12 of the main backing plate gasket 21A so as to penetrate in the gasket thickness direction (front-rear direction of the seat). Moreover, the suspension portion B12 is hooked and fixed to the respective hooks CL1 of the four retaining clips CL on the back surface of the gasket. The retaining clips CL are mounted on the clamping portions C14 of the main backing plate resin member 21C and are arranged in the seat width direction. Thus, the main backing plate cover 21B is disposed in a state where its middle portion is closely attached to the outer surface of the main backing plate gasket 21A.

[0040] The retaining clip CL is formed of an injection-molded product of resin having a hook CL1 for hooking the suspension portion B12 and a seat portion CL2 as a mounting portion for mounting to the main backing plate resin member 21C. The retaining clip CL is provided in such a manner that each hook CL1 is inserted into a corresponding hole formed in the main backing plate resin member 21C from the rear of the seat. Thus, the respective clamping portions C14 formed of elastic claws around the respective holes in the main backing plate resin member 21C are snap-fitted and engaged in a state of abutting against the rear surface of the seat portion CL2 of the retaining clip CL.

[0041] Thus, the above-mentioned seat portion CL2 is mounted in a state of being sandwiched in the front-rear direction between the rear surface of the main backing plate resin member 21C and the clamping portion C14. And by this mounting, each retaining clip CL is set in a state where the hook CL1 enters the hanging groove A12 of the main backing plate gasket 21A, and is in a state where the hook CL1 protrudes from the main backing plate resin member 21C toward the front of the seat.

[0042] As Figure 5As shown, the main backing plate resin member 21C is formed of an injection molded product having a shape that, when viewed from the rear, extends along the outer peripheral edge of the backing surface of the main backing plate gasket 21A and is in the shape of a frame. On the left and right and upper side edge portions of the main backing plate resin member 21C that extend in a frame shape when viewed from the rear, there are formed hook claws C11 for securing the ends of the front ends of the main backing plate cover 21B that are pulled into the backing surface of the gasket. The main backing plate resin member 21C is integrally fixed to the backing surface of the main backing plate gasket 21A via the main backing plate cover 21B by securing the ends of the main backing plate cover 21B to the respective hook claws C11 thereof.

[0043] As Figure 3 shown, in the eaves region of the main backing plate resin member 21C that overlaps the backing surface of the eaves portion of the main backing plate gasket 21A, there are formed support through holes C12 in the shape of square holes that penetrate in the vertical direction. Each of the support through holes C12 connects each of the support through holes A11 of the main backing plate gasket 21A to the space under the seat.

[0044] As Figure 3 shown, the main backing plate 21 is assembled from above the seat to the backrest frame 10 as follows. First, the eaves portion of the upper part of the main backing plate 21 that extends rearward of the seat is covered over the upper frame 12. At this time, the support through holes C12 of the main backing plate resin member 21C are set in a state of passing through the upper end portions of the corresponding support brackets 12A on the upper frame 12. Thereby, the eaves portion of the main backing plate 21 is set in a state of being hooked on the upper end portions of the support brackets 12A and being position-fixed.

[0045] Next, with the hooked eaves portion as a fulcrum, the main backing plate 21 is dropped so as to cover the lumbar plate 14 from the front of the seat. And accordingly, as Figure 6 shown, the middle fin portions 14A (hooking portions 14B) of the fin portions 14A that extend left and right of the lumbar plate 14 are hooked on the front surfaces of the respective hooked portions C13. Each of the hooked portions C13 is a portion that extends from the inner edge of the left and right frame side portions of the main backing plate resin member 21C.

[0046] Thereby, the vertically arranged fin portions 14A of the fin portions 14A (hooking portions 14B) hooked on the respective engaging portions C13 are pressed against the rear surfaces of the left and right frame side portions of the main backing plate resin member 21C. As a result, the left and right frame side portions of the main backing plate resin member 21C are in a state of being clamped front and rear by these fin portions 14A.

[0047] Moreover, the ends of the main backing plate cover 21B that extend downward from the lower part of the main backing plate 21 to the space under the seat are pulled rearward of the seat through the lower side of the lower frame 13 of the backrest frame 10 and are secured to the rear surface of the lower frame 13. Through the above assembly, the main backing plate 21 is set in a state where its upper, lower, and middle portions are respectively engaged with the backrest frame 10 or the lumbar plate 14.

[0048] Through the above assembly, when the main cushion plate 21 flexes in a bow shape bent forward of the seat as the lumbar plate 14 flexes, and when the bending is restored rearward of the seat, the main cushion plate 21 moves in the front-rear direction of the seat following the movement of the lumbar plate 14. In addition, when the position of the lumbar plate 14 is adjusted in the vertical direction, the fin portions 14A slide up and down along the main cushion plate resin member 21C, thereby appropriately avoiding this movement.

[0049] (Structure of each side cushion plate 22) Next, with reference to Figure 3 、 Figure 5 and Figure 9 , the structure of each side cushion plate 22 will be described. Each side cushion plate 22 has a side cushion pad 22A, a side cushion cover 22B, and a side cushion plate resin member 22C. The side cushion pad 22A is a seat cushion portion. The side cushion cover 22B is made of fabric and covers the side cushion pad 22A. The side cushion plate resin member 22C is provided on the back of the side cushion pad 22A.

[0050] Each side cushion plate 22 has substantially the same basic structure, but with the side airbag device 30 provided on the right side portion of the seat back 2, the shape for having a path for the airbag 31 to deploy and ensuring the installation space of the side airbag device 30 is different.

[0051] As Figure 9 shown, the side cushion pad 22A is formed of a polyurethane foam molded body. The side cushion pad 22A is formed such that the surface on the front side of the seat, that is, the cushion surface, has a shape of a protruding dike-like portion that stands up in a manner of bulging forward from the inner side to the outer side in the seat width direction.

[0052] The back of the side cushion pad 22A is formed into a concave curved surface shape that is hollowed out in a manner of being recessed along the above-mentioned dike-like protrusion. As Figure 3 and Figure 5 shown, the side cushion pad 22A also has a shape with an eaves portion that covers the top plate portion of the upper frame 12 from above the seat at its upper part.

[0053] The side cushion cover 22B covers the side cushion pad 22A from the front of the seat. The peripheral portions of the side cushion cover 22B in the up, down, left, and right directions are pulled into the back of the side cushion pad 22A and fixed. Specifically, the ends of the side cushion cover 22B in the up, down, left, and right directions are pulled into the back of the side cushion pad 22A. The ends pulled into the back of the side cushion pad 22A are hooked on the curved plate-like side cushion plate resin member 22C provided along the back of the cushion. Thereby, the side cushion cover 22B is fixed to the side cushion pad 22A.

[0054] By means of the above-mentioned hanging, the side cushion cover 22B is disposed on the entire outer surface of the side cushion liner 22A. In addition, the side cushion resin member 22C is fixed in a state of being pressed against the back surface of the cushion of the side cushion liner 22A by hanging on the respective ends of the side cushion cover 22B.

[0055] As Figure 5 and Figure 9 shown, the side cushion resin member 22C is an injection molded product formed in a shape that conforms to the concave curved surface of the back surface of the cushion of the side cushion liner 22A. The side cushion resin member 22C is formed with a region as a side support portion C26 that extends obliquely from the back side of the cushion to support the dike-shaped protruding portion of the side cushion liner 22A. Through this side support portion C26, the dike-shaped protrusion of the side cushion liner 22A is supported in a planar manner from the back side of the cushion. Thereby, the side support of the side cushion 22A for the side of the seated person's body can be appropriately performed.

[0056] Hook hanging claws C21 are formed on the peripheral edge portion of the side cushion resin member 22C. The hook hanging claws C21 fix the respective ends of the front end of the back surface of the cushion that are pulled into the side cushion cover 22B. In addition, as Figure 5 shown, an upper end fitting portion C22 that protrudes downward from the seat is formed in the eaves region of the side cushion resin member 22C that overlaps the back surface of the eaves portion of the side cushion liner 22A.

[0057] When assembling the side cushion 22 to the backrest frame 10 (refer to Figure 3 ), the upper end fitting portion C22 is inserted into the corresponding fitting holes 12B formed at the left and right end portions (shoulder openings) of the upper frame 12 from above the seat. Through the above insertion, the upper portion of the side cushion 22 is set in a state of being hooked on the upper frame 12 and being position-fixed.

[0058] As Figure 5 shown, a pedestal portion C23 that protrudes rearward from the seat is formed at the lower portion of the side cushion resin member 22C. A fitting clip C24 is installed at the front end of the pedestal portion C23. When assembling the side cushion 22 to the backrest frame 10 (refer to Figure 3 ), the fitting clip C24 is inserted into the corresponding circular hole-shaped engaging holes 11B formed at the rear edge portions of the lower ends of the respective side frames 11 along with snap fitting. In this way, the lower portion of the side cushion 22 is set in a state of being engaged with the lower portions of the respective side frames 11 and being position-fixed.

[0059] In addition, a fastening portion C25 is formed at the middle portion in the vertical direction of the side cushion resin member 22C. The fastening portion C25 is plate-shaped and extends obliquely rearward from the inner edge portion in the seat width direction toward the inner side in the seat width direction. As Figure 8As shown, the fastening part C25 is set to overlap with the front surface (the overlapping surface facing obliquely forward) of the fastening bracket 11A extending obliquely inward and rearward from each side frame 11 by assembling the side backing plate 22 to the backrest frame 10.

[0060] And, after being set as described above, a bolt B, which is a plug-in fastening structure, is inserted into the fastening part C25 and the fastening bracket 11A using a fastening tool (such as an impact screwdriver) not shown, and fastened. Thus, the fastening part C25 is fastened in a state of overlapping with the upper surface of the fastening bracket 11A.

[0061] (Structure of the side airbag device 30) Next, with reference to Figure 9 the structure of the side airbag device 30 will be described. The side airbag device 30 is installed on the right side (the outer side in the vehicle width direction) of the right side frame 11. The side airbag device 30 is formed in a long box shape extending in the vertical direction along the right side frame 11 (refer to Figure 4 ).

[0062] Specifically, the side airbag device 30 includes an airbag 31, an inflater 32, a housing 33, a guide plate 34, and a lining 35. The side airbag device 30 receives an input of a detection signal of a vehicle collision from an ECU of a vehicle not shown, and thereby injects gas from the inflater 32 into the airbag 31. Thus, the airbag 31 expands and unfolds toward the front of the seat. The airbag 31 breaks through the seat back 2 in a large range in the vertical direction of the seat back 2 and expands and unfolds into a shape of a long bag in front of the seat.

[0063] The housing 33 is a long box-shaped container that houses the airbag 31 and the inflater 32 inside. The upper and lower two parts of the inner side of the housing 33 are fixed to the right side part of the right side frame 11 by bolt fastening. The housing 33 has an open cross-sectional container structure in which the right front corner is opened by a long slit. When the airbag 31 expands and unfolds, the housing 33 pushes open the right front corner by its unfolding pressure, causing the airbag 31 to expand and unfold toward the front of the seat.

[0064] The housing 33 is arranged in such a way as to be located on the back side of the side backing plate resin member 22C. Therefore, an opening C27 for opening the unfolding area of the airbag 31 is formed in the side backing plate resin member 22C. This is to ensure the unfolding path of the airbag 31 bulging out from the housing 33 located on the back side of the side backing plate resin member 22C. The opening C27 is formed in a long rectangular opening shape so that substantially the entire area of the region facing the housing 33 is opened.

[0065] The guide plate 34 is composed of a longitudinally long plate-shaped member with an L-shaped cross-section made of metal. The guide plate 34 is fixed to the side portion at the rear of the housing 33 and is arranged to cover the right side portion. The guide plate 34 is arranged to extend forward from the right side portion of the housing 33 through the opening C27 of the side cushion resin member 22C towards the seat. Thus, the guide plate 34 covers the edge of the opening C27 from the inner side of the opening when the airbag 31 expands and unfolds. Therefore, the airbag 31 is protected from directly contacting the edge of the opening C27.

[0066] The lining cloth 35 is a longitudinally long guide cloth that guides the unfolding direction of the airbag 31. The lining cloth 35 is composed of one piece of cloth member. The lining cloth 35 wraps the housing 33 from the rear of the seat. Moreover, each end of the lining cloth that wraps the front end of the housing passes through the slit A21 of the side cushion gasket 22A from the opening C27 and is sewn to each sewing end B21 of the side cushion cover 22B. Each sewing end B21 is the end of each cover piece whose sewing will be broken by the unfolding pressure of the airbag 31.

[0067] The slit A21 formed in the side cushion gasket 22A is a hole for the airbag 31 that bulges forward from the opening C27 towards the seat to pass through when the airbag 31 expands and unfolds. The slit A21 extends through the side cushion gasket 22A in a strip-like shape throughout substantially the entire area in the vertical direction facing the housing 33.

[0068] The airbag 31 receives gas injection from the inflator 32, pushes open the housing 33, passes through the opening C27 of the side cushion resin member 22C, widens the slit A21 of the side cushion gasket 22A from the back side of the gasket, and bulges forward towards the seat. And the airbag 31 breaks the sewing of each sewing end B21 that is sewn to each end of the lining cloth 35 and constitutes the bursting line BL of the side cushion cover 22B by its unfolding pressure. As a result, the airbag 31 expands and unfolds forward from between each sewing end B21.

[0069] (Assembly method of the seat back 2) Next, a method of assembling the seat cushion body 20 to the backrest frame 10 will be described. Refer to Figure 3 , the seat cushion body 20 first assembles each side cushion 22 to the backrest frame 10 (side cushion assembly process) before the main cushion 21. The method of assembling each side cushion 22 to the backrest frame 10 is as described above.

[0070] After assembling each side cushion 22, the main cushion 21 is assembled to the backrest frame 10 (main cushion assembly process). Through the above steps, the seat cushion body 20 composed of three divided elements can be simply and appropriately assembled to the backrest frame 10. In addition, the steps of removing the seat cushion body 20 from the backrest frame 10 are the opposite of the above steps.

[0071] As described above, the seat back 2 of the present embodiment has the following structure. In addition, the reference numerals in parentheses below are the reference numerals corresponding to the respective structures shown in the above embodiment.

[0072] The seat back (2) has a seat cushion body (20) that elastically supports the seated person and a seat frame (10) that supports the seat cushion body (20) from the back side of the seat. The seat back (2) also has a lumbar plate (14) that is mounted on the seat frame (10) and can adjust the position of the seat in the front-rear direction that supports the seat cushion body (20) from the back side of the seat. The seat cushion body (20) has a seat cushion (21A) as a seat cushion portion and a support member (21C) fixed to the back surface of the seat cushion (21A), which is the back surface of the seat cushion. The support member (21C) has an engagement portion (C13) that directly engages with the lumbar plate (14) in a manner that can follow the movement of the lumbar plate (14) toward the rear of the seat.

[0073] According to the above structure, by moving the lumbar plate (14) forward in the seat, the support position of the lumbar plate (14) on the seat cushion body (20) can be adjusted forward in the seat. In addition, by moving the lumbar plate (14) backward in the seat, the support member (21C) of the seat cushion body (20) directly engages with the lumbar plate (14) at the engagement portion (C13). Thus, with such a structure, the seat cushion body (20) can appropriately move backward following the lumbar plate (14).

[0074] In addition, the seat cushion body (20) is composed of three divided elements, namely, a main cushion (21) that forms the central portion in the seat width direction and side cushions (22) that form both side portions in the seat width direction. The support member (21C) is provided on the back surface of the main cushion (21A) of the seat cushion (21A) that forms the main cushion (21). According to the above structure, even if the seat cushion body (20) is divided into the main cushion (21) and the side cushions (22), the main cushion (21) can appropriately follow the forward and backward movement of the lumbar plate (14).

[0075] In addition, the lumbar plate (14) has a pair of hook portions (14B) that protrude outward in the seat width direction at both edges in the seat width direction. The engagement portion (C13) of the support member (21C) directly engages with the lumbar plate (14) by being hooked on the surface of the pair of hook portions (14B) on the back side of the seat.

[0076] According to the above structure, the structure in which the engagement portion (C13) of the support member (21C) directly engages with the lumbar plate (14) can be embodied in a simple structure by hooking the engagement portion (C13) on a pair of hook portions (14B) that protrude from both edges in the seat width direction of the lumbar plate (14) in a manner that functions appropriately.

[0077] In addition, the lumbar plate (14) adjusts its protruding position by flexing bow-shaped forward relative to the seat frame (10), and can also adjust its position in the height direction. According to the above structure, by hooking the engaging portion (C13) of the support member (21C) from the seat back side to a pair of hooking portions (14B) extending from both edges in the seat width direction of the lumbar plate (14), the flexure and height position adjustment of the lumbar plate (14) can be appropriately allowed through the sliding of the abutting surfaces of each other.

[0078] In addition, the lumbar plate (14) has fin portions (14A) that extend outward in the seat width direction at a plurality of positions in the height direction of both edges in the seat width direction, expanding the support surface. A pair of hooking portions (14B) are any of the plurality of fin portions (14A). According to the above structure, by using the structure of the fin portions (14A) of the lumbar plate (14) that expand the support surface, the engaging portion (C13) of the support member (21C) can be reasonably and appropriately hooked to the lumbar plate (14).

[0079] 《Regarding Other Embodiments》 In addition to the above embodiments, the present disclosure can also be implemented in various ways.

[0080] The seat back of the present disclosure can also be configured as the seat back of a seat mounted on a vehicle other than an automobile such as a railway vehicle, and can also be configured as the seat back of a seat mounted on a means of transportation other than a vehicle such as an airplane or a ship. In addition, the seat cushion body can be composed of a single non-divided structure in addition to the structure composed of three divided elements divided into a main cushion plate and each side cushion plate.

[0081] The support member provided on the back surface of the seat cushion and fixed to the seat frame can be made of metal in addition to resin. In addition, the support member can also be composed of a back material made of a non-woven fabric or the like that is integrally impregnated and cured by integral foam molding with the seat cushion and is provided on the back surface of the seat cushion.

[0082] The engaging portion that directly engages the support member with the lumbar plate can also be formed of an engaging structure other than hooking, such as a combination based on a hook-and-loop fastener, a snap fit based on a clip, a press fit of a pin, a structure that can slidably fit into a long hole, etc. In addition to engaging the support member with the edge portion on both sides or one side of the lumbar plate, the engaging portion can also be an object that engages the support member with the middle portion of the lumbar plate. In addition, the engaging position of the engaging portion with respect to the lumbar plate can be one or more places.

[0083] In addition to fabric, the main cushion plate cover and the side cushion plate cover can each be made of a leather material.

[0084] The various embodiments described in detail with reference to the accompanying drawings are representative examples of the present invention and do not limit the present invention. The detailed description is for teaching those skilled in the art for making, using, and / or implementing various forms of the present teachings and does not limit the scope of the present invention. Moreover, for providing an improved seat back and / or its manufacturing method and usage method, the above-mentioned additional features and teachings can be applied and / or used separately or in combination with other features and teachings.

Claims

1. A seat backrest, comprising: a seat cushion body that elastically supports a sitter; a seat frame that supports the seat cushion body from the back side of the seat; and a lumbar plate that is mounted on the seat frame and is capable of adjusting the position in the front-rear direction of the seat that supports the seat cushion body from the back side of the seat, wherein the seat cushion body has: a seat pad as a seat cushion portion; and a support member that is fixed to the back surface of the seat pad, which is the back surface of the seat cushion on the back side of the seat, wherein the support member has an engaging portion that directly engages with the lumbar plate in a manner capable of following the movement of the lumbar plate toward the rear of the seat.

2. The seat backrest according to claim 1, wherein the seat cushion body is composed of three divided elements, namely, a main cushion plate that forms the central portion in the seat width direction and side cushion plates that form both side surface portions in the seat width direction, and the support member is provided on the back surface of the main cushion pad of the seat pad that forms the main cushion plate.

3. The seat backrest according to claim 1 or 2, wherein the lumbar plate has a pair of hooking portions that project outward in the seat width direction at both edges in the seat width direction thereof, and the engaging portion of the support member directly engages with the lumbar plate by being hooked on the surface on the back side of the seat by the pair of hooking portions.

4. The seat backrest according to claim 3, wherein the lumbar plate adjusts the projecting position by flexing into an arcuate shape toward the front of the seat with respect to the seat frame, and is also capable of adjusting the position in the height direction.

5. The seat backrest according to claim 3, wherein the lumbar plate has fin portions that project outward in the seat width direction at a plurality of positions in the height direction at both edges in the seat width direction thereof, so as to expand the support surface, and the pair of hooking portions are any one of the plurality of fin portions.

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