Seat back

Abstract

This seatback provides sufficient headrest cushioning thickness to enhance protection for the occupant's head and neck. [Solution] In a seat back comprising a seat back frame (10) that forms the skeleton of the seat back, a headrest (30) that supports the head of the occupant, and a headrest pillar (40) that is attached to the upper part of the seat back frame and supports the headrest, the headrest pillar is provided to have a fixing portion (41) that is fixed to the upper front end of the seat back frame and a first bent portion (42) that begins to extend rearward from the fixing portion.

Description

Technical Field

[0001] The present invention relates to a seat back having a headrest supported by a headrest pillar.

Background Art

[0002] At the upper part of the seat back of a vehicle seat, a headrest is provided to protect the head and neck of the seated person from the impact during a rear collision. Generally, the headrest is fixed to the upper part of a seat back frame which forms the skeleton of the seat back. Conventionally, as a method of fixing the headrest to the seat back frame, a bracket fixed to a headrest frame which is the core material of the headrest is positioned on the front side of the seat back frame, and the upper horizontal part of the seat back frame is sandwiched from the front and back by this bracket and a plate arranged on the rear side of the seat back frame, and fixed by tightening bolts (for example, Patent Document 1). Also, a pillar guide attachment frame is provided parallel to the upper frame of the seat back frame, and a pair of cylindrical pillar guides are fixed so as to straddle the upper frame and the pillar guide attachment frame, and a pillar which is the core material of the headrest is inserted into the pillar guide, thereby attaching the headrest to the upper part of the seat back frame (for example, Patent Document 2).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the headrest invention described in Patent Document 1 and the vehicle seat described in Patent Document 2, the headrest is positioned on the front side of the seat back frame, making it impossible to ensure sufficient thickness of the headrest cushion. Therefore, there is a need for greater strength against impact loads caused by collisions.

[0005] On the other hand, in order to increase the thickness of the headrest cushion, it is conceivable to fix the lower end of the pillar supporting the headrest to the upper rear surface of the seat back frame by welding or other means. However, if the lower end of the pillar is fixed to the upper rear surface of the seat back frame in this way, the moment caused by the force applied from the occupant's head to the headrest during a collision will act to peel off the welded part of the pillar, thus requiring further improvement in the rigidity of the joint between the headrest pillar and the seat back frame.

[0006] This invention was made in view of the above-mentioned problems, and aims to provide a seat back that can enhance the function of protecting the occupant's head and neck by ensuring sufficient thickness of the headrest cushion. Another object of the present invention is to provide a seat back that can increase the mounting rigidity of the headrest pillar to the seat back frame. [Means for solving the problem]

[0007] To solve the above problem, the seat back according to the invention described in claim 1 is: The seat back frame, which forms the skeleton of the seat back, A headrest that supports the head of the seated person, A headrest pillar connected to the upper part of the seat back frame and supporting the headrest, A seat back equipped with, The aforementioned headrest is A fixing part fixed to the upper front end of the aforementioned seat back frame, A first bent portion that begins to extend rearward from the aforementioned fixed portion, It is characterized by having the following features.

[0008] The invention described in claim 2 is, in the seat back described in claim 1, The aforementioned seat back frame is A pair of side frames spaced apart in the left-right direction, The system comprises an upper frame that is horizontally positioned between the upper ends of the pair of side frames and whose ends are connected to the side frames, The headrest pillar is characterized in that its lower end is fixed to the front surface of the upper frame, and it has a second bent portion that begins to extend upward relative to the first extended portion extending from the first bent portion, near and above the fixing portion with the upper frame.

[0009] The invention described in claim 3 is, in the seat back described in claim 2, The second bent portion is characterized in that it is positioned forward of the rear end of the upper frame in the seat-front-rear direction.

[0010] The invention described in claim 4 is, in the seat back described in claim 3, The headrest pillar is characterized in that it has a third bent portion that begins to extend forward from the second bent portion, between the upper end of the headrest pillar and the second bent portion.

[0011] The invention described in claim 5 is, in the seat back described in claim 4, The third bent portion is characterized in that it is positioned further back in the seat-front-rear direction than the rear end of the upper frame.

[0012] The invention described in claim 6 is a seat back according to any one of claims 1 to 5, The headrest is provided with a support member, The headrest is characterized in that, at a position rearward in the front-rear direction of the seat from the first bend, the headrest is attached to the upper end of the headrest pillar via the support member.

[0013] The invention according to claim 7 is the seat back according to claim 6, wherein the support member includes a plate portion to which the headrest is coupled, an extending portion extending rearward from the plate portion, and an extending portion extending rearward from the plate portion, by fixing the extending portion to the upper end portion of the headrest pillar, it is fixed to the headrest pillar, the extending portion is fixed to the upper end portion of the headrest pillar at at least three or more locations.

[0014] The invention according to claim 8 is the seat back according to claim 7, wherein the headrest pillar has a pair of fourth bending portions that start to extend so as to slope upward toward the center side of the seat back at a position slightly higher than the third bending portion.

[0015] The invention according to claim 9 is the seat back according to claim 8, wherein it has a pair of fifth bending portions that are bent so as to change the direction horizontally at a portion sandwiched between the pair of fourth bending portions, the extending portion is fixed to the upper end portion of the headrest pillar at a position avoiding the fifth bending portion.

[0016] The invention according to claim 10 is the seat back according to claim 9, wherein the lower end portion of the headrest is located below the third bending portion.

Advantages of the Invention

[0017] According to the invention described in claim 1, it is possible to sufficiently secure the thickness of the cushion of the headrest and enhance the function of protecting the head and neck of the seated person. In addition, it is possible to enhance the mounting rigidity of the headrest pillar to the seat back frame.

[0018] According to the invention described in claim 2, a headrest pillar of a desired shape can be formed with good reproducibility.

[0019] According to the invention described in claim 3, the amount of rearward protrusion of the headrest pillar can be reduced, contributing to a more compact headrest in the front-to-back direction.

[0020] According to the invention described in claim 4, the upper part of the headrest pillar is tilted forward to increase resistance to forces acting from the front, making it less susceptible to plastic deformation.

[0021] According to the invention described in claim 5, the bending angle at the third bent portion of the headrest pillar can be increased.

[0022] According to the invention described in claim 6, the rigidity of the connection between the main body of the headrest and the upper part of the headrest pillar is improved. Furthermore, by ensuring sufficient thickness of the headrest cushion and utilizing the flexure of the headrest pillar itself, the function of protecting the occupant's head and neck can be enhanced.

[0023] According to the invention described in claim 7, the support member (headrest frame) can be easily connected to the headrest pillar.

[0024] According to the invention described in claim 8, it becomes possible to form a headrest pillar of a desired shape with good reproducibility.

[0025] According to the invention described in claim 9, the headrest support member can be fixed (welded) to the upper end of the headrest pillar relatively easily.

[0026] According to the invention described in claim 10, a headrest body having a desired vertical length can be positioned at an appropriate height. [Brief explanation of the drawing]

[0027] [Figure 1]This is a perspective view showing an example of the configuration of the structural members inside the headrest, which is provided at the top of the seat back according to the present invention. [Figure 2] This is a front view showing an example of the configuration of the upper part of the seat back frame that constitutes the seat back according to the present invention. [Figure 3] Figure 1 is a side view showing the configuration of the structural components inside the headrest, as seen from the side. [Figure 4] This is an exploded perspective view of the headrest that constitutes the seat back of the embodiment. [Figure 5] This is a perspective view showing the connection between the headrest pillar and the bracket that makes up the headrest. [Figure 6] This is a cross-sectional side view showing the internal configuration of the headrest of the embodiment. [Modes for carrying out the invention]

[0028] Hereinafter, embodiments of the seat back and vehicle seat according to the present invention will be described with reference to the drawings. Of these, Figure 1 is a perspective view showing an example of the configuration and mounting structure of the frame members inside the headrest provided at the top of the seat back, Figure 2 is a front view showing an example of the configuration of the upper part of the seat back frame that constitutes the seat back shown in Figure 1, Figure 3 is a side view showing the configuration of the frame members inside the headrest shown in Figure 1 as seen from the side, and Figure 4 is an exploded perspective view of the headrest. In the following description, unless otherwise specified, the direction of travel of the vehicle will be referred to as the front, and the opposite direction as the rear.

[0029] As shown in Figure 1, the main body 32 of the headrest provided on the upper part of the seat back according to this embodiment is connected to the front side of the upper part of the headrest pillar 40, which has an inverted U shape when viewed from the front and whose lower end is fixed to the front of the upper part of the seat back frame 10, which is the skeleton of the seat back, by welding or the like, and is supported by the seat back frame 10 via the headrest pillar 40.

[0030] Specifically, the headrest has a base frame 31 that protrudes rearward from the backrest, and a headrest body 32 that is attached to the base frame 31, with the rear end of the base frame 31 fixed to the upper part of the headrest pillar 40 by welding or the like. The headrest body 32 has components that serve as shock-absorbing pads or covers, which will be explained in detail later. The headrest pillar 40 is bent so as to bulge outwards towards the rear, and the lower ends of the legs 40a and 40b are welded to the front surface of the protruding surface 122 of the upper frame 12 that constitutes the seat back frame 10. By providing the upper frame 12 having the protruding surface 122 and fixing the lower ends of the legs 40a and 40b of the headrest pillar 40 to it, the welding area can be widened, and the joint rigidity of the headrest pillar 40 can be increased.

[0031] On the other hand, the seat back frame 11 comprises a pair of left and right side frames 11A and 11B, and an upper frame 12 that spans the widthwise direction between the upper ends of the side frames 11A and 11B, and is formed in a substantially inverted U shape when viewed from the front-rear direction of the seat. The upper frame 12 and the side frames 11A and 11B are joined by welding to create a rigid connection. Although not shown in the diagram, a lower frame is horizontally mounted and rigidly connected between the lower ends of the side frames 11A and 11B. On the front side of the seat back frame 10, a cushion pad made of foamed rubber or foamed urethane, and a pan frame that supports the cushion pad are arranged, and the surface of the cushion pad is covered with a skin.

[0032] When the seat back equipped with a headrest according to this embodiment is used in a vehicle seat, the lower end of the seat back frame 10 is connected via a hinge to the rear end of the seat cushion frame, which forms the skeleton of the seat cushion, so as to be tiltable. The side frames 11A and 11B, which form the framework of the seat back, may be composed of an inner side frame and an outer side frame, or they may be composed of pipes or pan frames.

[0033] The upper frame 12 has a lower base portion 121 and a protruding surface portion 122 that protrudes forward from the base portion 121, and is provided with an opening 12a for inserting the blower 21. As shown in Figure 2, there is a horizontal piece portion 123 between the base portion 121 and the protruding surface portion 122, and an opening is also provided in this horizontal piece portion 123, so that the opening 12a is formed to form an L shape in side view from the base portion 121 to the protruding surface portion 122. As described above, the protruding surface portion 122 has a shape that protrudes forward from the base portion 121, and the opening 12a is formed from the base portion 121 to the protruding surface portion 122, so that a storage recess capable of housing the blower 21 is formed. In Figure 2, reference numeral 124 denotes the joint fixing portion between both sides of the upper frame 12 and the upper ends of the side frames 11A and 11B.

[0034] Next, the detailed configuration and support structure of the headrest 30 in this embodiment will be described. Figure 3 shows the configuration of the internal frame members (excluding the cushioning members) of the headrest 30 shown in Figure 1, and the support structure including the headrest pillar 40 that supports them, as viewed from the side. As described above, in this embodiment, the headrest pillar 40 is bent so as to bulge outwards toward the rear, and the lower ends of the leg portions 40a and 40b are fixed to the front surface of the protruding surface portion 122 of the upper frame 12 by welding.

[0035] Therefore, the lower ends of the leg portions 40a and 40b become fixing portions 41 for fixing the headrest pillar 40 to the upper front of the seat back frame 10. In this way, by fixing the fixing portion 41 to the upper front of the seat back frame 10, even if the impact from the occupant's head acts on the headrest pillar 40 during a rearward vehicle collision, the force will not be able to peel off the welded portion of the fixing portion 41. Thus, the headrest pillar 40 can be fixed to the seat back frame 10 more firmly than if the fixing portion 41 were fixed to the upper rear surface of the seat back frame 10.

[0036] Furthermore, the headrest pillar 40 of this embodiment is formed such that a pair of left and right legs 40a, 40b each have a first bent portion 42 that begins to extend rearward from the upper part of the fixing portion 41, a second bent portion 43 that begins to extend upward relative to the straight line connecting the fixing portion 41 and the first bent portion 42 above the rear end of the upper frame 12, and a third bent portion 45 that begins to extend forward relative to the straight line connecting the first bent portion 42 and the second bent portion 43 between the upper horizontal portion 44 of the headrest pillar 40 and the second bent portion 43. The headrest pillar 40 can be formed by bending a steel rod or steel pipe. The headrest frame 31 is connected to the upper horizontal portion 44 of the headrest pillar 40. The bending angle θ1 at the first bend portion 42 should preferably be less than 90 degrees.

[0037] As described above, the headrest pillar 40 is bent at three bending points, so that the headrest 30 is attached to the headrest pillar 40 behind the front of the upper part of the seat back frame 10. This ensures sufficient cushioning thickness in the headrest body 32, significantly enhancing its ability to protect the occupant's head and neck from impact during a collision. Furthermore, the headrest pillar 40 has a shape in which the central part bulges backward when viewed from the side, and the part above the third bend 45 is tilted forward, thereby increasing its resistance to forces acting from the front and making it less susceptible to plastic deformation. Furthermore, by providing multiple bending points in the headrest pillar 40, the headrest pillar can be bent with greater reproducibility compared to forming it by curving the entire structure.

[0038] Here, the condition for the portion above the third bend 45 to have a forward-leaning shape is that, if the backward bending angle at the first bend 42 is θ1, the upward bending angle at the second bend 43 is θ2, and the forward bending angle at the third bend 45 is θ3, then θ1 < (θ2 + θ3). Note that if the bending angles at each bend are set such that θ1 = (θ2 + θ3), then the portion above the third bend 45 will be parallel to the fixing portion 41 in a side view. Furthermore, if a force acting backward from the headrest 30 is applied to the upper end of the headrest pillar 40, the bending moment generated in the second bend 43 will be greater than the bending moment generated in the third bend 45. Therefore, it is conceivable to set the bending angles in the second and third bends such that θ2 > θ3.

[0039] Furthermore, the headrest pillar 40 of this embodiment is formed such that the connecting portion 40c (see Figure 1) begins to extend upward toward the center of the seat back at a position slightly higher than the third bending portion 45, and has a pair of fifth bending portions 47 that are bent to change direction horizontally in the portion sandwiched between the pair of fourth bending portions 46. In this specification, the space between the left and right pairs of fourth bending portions 46 of the headrest pillar 40 is referred to as the connecting portion, and the space from the fourth bending portion 46 to the fixing portion 41 is referred to as the leg portion.

[0040] Furthermore, the headrest frame 31, which is connected to the upper horizontal portion 44 of the headrest pillar 40, has, as shown in Figure 5, a trapezoidal plate portion 311 arranged almost vertically, and a roof-shaped extension portion 312 that extends rearward from the upper edge and the left and right slanted edges of the plate portion 311a, with its rear end fixed to the headrest pillar 40 by welding. By providing the extension portion 312 in this way, the headrest frame 31, which serves as a support member for the headrest body portion 32, can be easily connected to the headrest pillar 40.

[0041] Here, the plate portion 311 has a pair of bolt insertion holes 31a through which bolts for fixing the bracket 32A described later are inserted, and the extended portion 312 has two openings 31b for weight reduction. The headrest frame 31 is then fixed to the circumferential surface of the upper horizontal portion 44 of the headrest pillar 40 by welding at the tips (rear ends) of the three wall portions that sandwich the two openings 31b of the extended portion 312.

[0042] As described above, the headrest frame 31 is fixed to the upper part of the headrest pillar 40 by welding at three points. This structure allows for a reduction in the welding area while maintaining the necessary joint rigidity, thereby improving work efficiency. Furthermore, if welding were simply performed at three points without providing the two openings 31b, variations in welding locations would easily occur between products. However, by providing the two openings 31b and limiting the welding locations, product variations can be reduced. Furthermore, the headrest frame 31, which serves as a support member for the headrest body 32, is attached to the headrest pillar 40 such that the support plate portion 311 is positioned in front of the upper end of the headrest pillar 40 in the front-rear direction of the seat. This allows the force from the occupant's head acting on the headrest to be efficiently transmitted to and absorbed by the headrest pillar 40.

[0043] On the other hand, as shown in Figure 4, the headrest body 32 includes a U-shaped headrest mounting bracket 321 fixed to the front surface of the plate portion 311 of the headrest frame 31 by bolts and nuts, and a pressure receiving member 322 made of a rigid material that is positioned in contact with the front surface of the bracket 321 and receives the impact load from the occupant's head during a rear collision and transmits it directly to the headrest frame 31 via the bracket 321. The bracket 321 has flanges 321a formed at the front ends of the left and right side walls. The pressure receiving member 322 has a stepped portion 322a on its front surface, with the central portion being one step higher than the edge, and a plurality of small holes 322b formed in this stepped portion.

[0044] Furthermore, the headrest body 32 includes a rear inner case 323 made of synthetic resin having an opening 323a large enough to accommodate the main body of the bracket 321, and a front inner case 324 also made of synthetic resin having an opening 324a large enough to accommodate the front stepped portion 322a of the pressure receiving member 322. These rear inner cases 323 and front inner cases 324 are formed to be slightly larger than the pressure receiving member 322 when viewed from the front, and each has multiple screw insertion holes 323b and 324b formed along its periphery. They are configured to be joined together by inserting bolts through these screw insertion holes 323b and 324b and screwing nuts onto them.

[0045] Therefore, when fixing the bracket 321 to the headrest frame 31, it is fixed in a state where it is fitted into the opening 323a of the rear inner case 323, and with the front stepped portion of the pressure receiving member 322 fitted into the opening 324a of the front inner case 324, it is joined to the front surface of the rear inner case 323, and then the front inner case 324 and the rear inner case 323 are integrated with bolts and nuts. As a result, the edge of the opening 323a of the rear inner case 323 comes into contact with the rear surfaces of the left and right flanges 321a of the bracket 321, and the rear surface of the pressure receiving member 322 comes into contact with the front surface of the flanges 321a. This allows the pressure-receiving member 322 to be sandwiched between the front inner case 324 and the rear inner case 323, and then fixed to the headrest frame 31 via the bracket 321, as shown in Figure 3. In addition, the rear inner case 323 and the front inner case 324 function as protective members that cover the outer edge of the pressure-receiving member 322.

[0046] Furthermore, in the headrest body 32 of this embodiment, a shock-absorbing pad 325 made of foamed rubber or foamed urethane is provided on the front side of the front inner case 324. Further on the front side of the pad 325, a slab (urethane slab) 326 made of a softer material than the pad 325 is provided to improve the feel when the sitter rests their head on the headrest, and the front side of the slab 326 is covered with a front cover 327 made of an elastic material. The pad 325 is formed to be slightly larger than the front inner case 324 when viewed from the front. In addition, a shallow recess is formed on the front of the pad 325 for providing space for the slab 326, preventing the slab 326 from moving (shifting).

[0047] As described above, because multiple small holes 322a are formed in the stepped portion of the pressure-receiving member 322, when a vehicle collision occurs from the rear and the occupant's head hits the headrest, causing the slab 326 and pad 325 to compress and deform, the air inside can escape to the rear through the small holes 322a of the pressure-receiving member 322, thereby reducing the impact on the head.

[0048] Furthermore, in the headrest body 32, a bowl-shaped rear cover 328 that is recessed towards the rear is provided on the rear side of the rear inner case 323. The rear cover 328 has an opening 328a that corresponds to the shape of the headrest frame 31, and each of the four corners on the inside of the bowl is provided with a locking piece 328b that protrudes forward and has a claw at its tip. Although not shown in Figure 4, a locking hole is formed in the rear inner case 323 in the part corresponding to the locking piece 328b, and the rear cover 328 is locked to the rear side of the rear inner case 323 by the claw at the tip of the locking piece 328b engaging with the locking hole in the rear inner case 323 (see Figure 6).

[0049] Figure 6 is a cross-sectional side view showing the headrest body 32 of this embodiment assembled to the headrest frame 31. As shown in Figure 6, in the headrest body 32 of this embodiment, the pad 325 is attached to the front side of the front inner case 324 so as to cover the front surface and edges of the front inner case 324, and the front cover 327 is attached to cover the front surface and edges of the pad 325. In addition, a pressing wire 329 made of an elastic material such as spring material is disposed between the lower ends of the rear inner case 323 and the front inner case 324.

[0050] As shown in Figure 4, the pressing wire 329 is bent in the middle to form a semi-rectangular shape, and the shaft portions at both ends are inserted into engagement portions (not shown) provided in the front inner case 324. As shown in Figure 6, the central hook-shaped portion of the pressing wire 329 is arranged to slope downward toward the front, and its tip is configured to engage with the lower edge of the front inner case 324 from behind. As a result, the lower edge of the front inner case 324 is pressed forward, and the pad 325 covering the front is compressed and deformed so that the thickness of the portion slightly inward from the lower edge becomes smaller than that of the edge, thereby making it difficult for the edge of the pad 325 to come off the front inner case 324.

[0051] Furthermore, in the headrest of this embodiment, as shown in Figure 6, a decorative cover 33 for covering the rear of the headrest frame 31 and the connecting portion 40c at the top of the headrest pillar 40 is provided on the rear side of the rear inner case 328. Specifically, the decorative cover 33 is provided with an L-shaped mounting bracket 33a that protrudes forward from the top of the decorative cover 33. This mounting bracket 33a is fixed to the upper surface of the headrest frame 31 by a screw 33b, thereby attaching the decorative cover 33 to the top of the headrest pillar 40. As described above, by providing the decorative cover 33, the headrest frame 31 and bracket 321 are not directly visible from the rear, thereby improving the appearance of the seat back.

[0052] Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment and can be implemented with various modifications without departing from the spirit of the invention. For example, in the above embodiment, the bracket 321 for fixing the headrest body 32 to the headrest frame 31 is arranged to form a U shape when viewed from above, but the bracket 321 may be arranged to form a U shape when viewed from the side. Alternatively, the bracket 321 may be formed in the shape of a box with one side open, and flanges may be provided on each of the four edges of the opening.

[0053] Furthermore, in the embodiment, the headrest pillar 40 is formed to have two legs 40a, 40b and a connecting portion 40c provided between the upper parts of the legs 40a, 40b, but it may also consist of only one pillar arranged in the vertical direction. However, by having a configuration with two legs 40a, 40b as in the embodiment above, the torsional strength can be increased compared to the case of a single pillar. Also, although it has been explained that the base frame 31 is fixed to the headrest pillar 40 by welding or the like, it may also be configured to have a flange on the headrest pillar 40 and be connected to the flange with bolts and nuts. In this case, the bracket 321 can be omitted.

[0054] Furthermore, although the above embodiment described that the fixing portion 41 of the headrest pillar 40 is fixed to the front surface of the upper frame 12 by welding, it may also be fixed using an omega-shaped fastener (saddle band) and bolts and nuts instead of welding. In addition, for example, the fixing portion 41 of the headrest pillar 40 can be made into a double-pipe structure to allow for adjustment of the headrest height. Furthermore, although the above embodiments described an example of applying the seat back according to the present invention to a vehicle seat, the present invention is not limited to vehicle seats and can also be applied to seats for vehicles such as ships and aircraft, or to seats (sofas) as furniture. [Explanation of symbols]

[0055] 10 Seat back frame 11A, 11B Side Frame 12 Upper frame 121 Base section 122 Projecting surface part 30 headrests 31 Headrest Frame 32 Headrest main body 321 Bracket 321a Flange section 322 Pressure-receiving member 322a Stepped section 322b Small hole 323 Rear inner case 323a opening 324 Front inner case 324a opening 325 pads 326 Slab 327 Front cover 328 Rear cover 328a opening 328b Locking piece 329 Compression wire 33 Makeup cover 33a Mounting piece 33b Screw 40 Headrest Pillar 41 Fixed part 42 1st bending point 43 Second bending point 44 Upper horizontal section 45 Third bending point 46 4th bending point 47 5th bending point

Claims

1. The seat back frame, which forms the skeleton of the seat back, A headrest that supports the head of the seated person, A headrest pillar connected to the upper part of the seat back frame and supporting the headrest, A seat back equipped with, The aforementioned headrest pillar is A fixing part fixed to the upper front end of the aforementioned seat back frame, A first bent portion that begins to extend rearward from the aforementioned fixed portion, A seat back characterized by having the following features.

2. The aforementioned seat back frame is A pair of side frames spaced apart in the left-right direction, The system comprises an upper frame that is horizontally positioned between the upper ends of the pair of side frames and whose ends are connected to the side frames, The seat back according to claim 1, characterized in that the headrest pillar has a lower end fixed to the front surface of the upper frame, and a second bent portion that begins to extend upward relative to the first extended portion extending from the first bent portion, near and above the fixing portion with the upper frame.

3. The seat back according to claim 2, characterized in that the second bent portion is positioned forward of the rear end of the upper frame in the seat-front-rear direction.

4. The seat back according to claim 3, characterized in that the headrest pillar has a third bent portion that begins to extend forward from the second bent portion between the upper end of the headrest pillar and the second bent portion.

5. The seat back according to claim 4, characterized in that the third bent portion is positioned rearward in the seat-front-rear direction from the rear end of the upper frame.

6. The headrest is provided with a support member, The seat back according to claim 4 or 5, characterized in that the headrest is attached to the upper end of the headrest pillar via the support member at a position rearward in the front-rear direction of the seat from the first bent portion.

7. The support member comprises a plate portion to which the headrest is attached, and an extended portion that extends rearward from the plate portion. The extended portion is fixed to the upper end of the headrest pillar, thereby being fixed to the headrest pillar. The seat back according to claim 6, characterized in that the extended portion is fixed to the upper end of the headrest pillar at least three or more locations.

8. The seat back according to claim 7, characterized in that the headrest pillar has a pair of fourth bends that begin to extend upward toward the center of the seat back at a position slightly higher than the third bend.

9. It has a pair of fifth bent portions that are bent so as to change direction horizontally in the portion sandwiched between the pair of fourth bent portions, The seat back according to claim 8, characterized in that the extended portion is fixed to the upper end of the headrest pillar at a position avoiding the fifth bent portion.

10. The seat back according to claim 9, characterized in that the lower end of the headrest is located below the third bent portion.

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