Seat back frame and vehicle seat

Abstract

To provide a seat back frame which easily secures strength of a belt anchor bracket.SOLUTION: A seat back frame 20 having right and left side frames 24 and an upper frame 26 laid between upper ends of the right and left side frames 24, comprises a frame body 22 on which a retractor of a seat belt device is mounted, and a belt anchor bracket 40 on which right and left leg parts 46A are fixed to the upper frame 26, and an upper wall part 46B faces the upper end of one side frame 24 from above the seat back. The belt anchor bracket 40 has a winding part where a seat belt is to be retracted by the retractor. At the upper end of the one side frame 24, an upper extension part 24E that projects to above the seat back on a seat back front side in front of a fixing part to be fixed to the upper frame 26 at the right and left leg parts 46A, and which faces a lower surface of the upper wall part 46B from therebelow, is formed.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a vehicle seat, and more particularly to a seat back frame. [Background technology]

[0002] In the vehicle seat described in Patent Document 1 below, a back frame disposed within the seat back has a pair of left and right side frames and an upper frame spanning the upper ends of the left and right side frames. A retractor of a seat belt device is attached to this back frame. The seat belt wound by this retractor is wound around a belt guide (belt anchor bracket) disposed at the shoulder of the seat back and fixed to the upper end of the back frame. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2020-199923 Summary of the Invention [Problem to be solved by the invention]

[0004] In the above prior art, when a vehicle crashes, an excessive load from the occupant who tries to inertially move toward the front of the seat acts on the belt anchor bracket via the seat belt, so ensuring the strength of the belt anchor bracket becomes an issue.

[0005] SUMMARY OF THE INVENTION In consideration of the above, an object of the present invention is to provide a seat back frame and a vehicle seat in which the strength of a belt anchor bracket can be easily ensured. [Means for solving the problem]

[0006] The seatback frame of the first embodiment has left and right side frames and an upper frame spanning between the upper ends of the left and right side frames, a frame main body to which a retractor of a seat belt device is attached, and left and right legs fixed to the upper frame, an upper wall portion spanning between the upper ends of the left and right legs facing the upper end of one of the left and right side frames from above the seat back, and a belt anchor bracket having a winding portion around which the seat belt to be wound into the retractor is wound, and an upward extension portion is formed at the upper end of one of the side frames, which protrudes toward the upper side of the seat back further forward than the fixed portions of the left and right legs to the upper frame, and faces the underside of the upper wall portion from below the seat back.

[0007] In the seatback frame of the first aspect, the frame main body has left and right side frames and an upper frame spanning between the upper ends of the left and right side frames. A retractor of a seat belt device is attached to the frame main body. Left and right legs of a belt anchor bracket are fixed to the upper frame of the frame main body. The belt anchor bracket has an upper wall portion spanning between the upper ends of the left and right legs and a winding portion around which the seat belt to be retracted by the retractor is wound, and the upper wall portion faces the upper end of one of the left and right side frames from above the seatback.

[0008] According to this aspect, an upward extension is formed on the upper end of the one side frame, protruding upward toward the seat back and further forward than the fixed portions of the left and right legs of the belt anchor bracket to the upper frame. This upward extension faces the lower surface of the upper wall portion of the belt anchor bracket from the lower side of the seat back. Therefore, when an excessive load from the seat belt acts on the belt anchor bracket, the lower surface of the upper wall portion of the belt anchor bracket contacts the upward extension, thereby transmitting the load to the one side frame. This makes it easy to ensure the strength of the belt anchor bracket.

[0009] The seat back frame of the second aspect is the seat back frame of the first aspect, wherein the upward extension portion faces the lower surface of the upper wall portion with a gap therebetween.

[0010] In the seat back frame of the second aspect, the upward extension formed on the upper end of one of the side frames of the frame main body faces the underside of the upper wall of the belt anchor bracket with a gap therebetween, thereby preventing the upward extension from accidentally interfering with the underside of the upper wall of the belt anchor bracket due to manufacturing variations when fixing the left and right legs of the belt anchor bracket to the upper frame of the frame main body.

[0011] The seatback frame of the third aspect is the first or second aspect, wherein one of the side frames has a side wall portion whose thickness direction is the left-right direction of the seatback and a front flange portion extending from the front end of the side wall portion inward in the left-right direction of the seatback, and the upward extension portion is formed by a part of the side wall portion and a part of the front flange portion.

[0012] In the seatback frame of the third aspect, one side frame of the frame main body has a side wall portion whose thickness direction is the left-right direction of the seatback and a front flange portion that extends inward in the left-right direction of the seatback from the front end of the side wall portion. An upward extension portion formed at the upper end of one side frame is composed of a part of the side wall portion and a part of the front flange portion. This makes it easier to ensure the strength of the upward extension portion compared to, for example, when the upward extension portion is composed of only a part of the side wall portion or only a part of the front flange portion.

[0013] The seat back frame of the fourth aspect is any one of the first to third aspects, in which the belt anchor bracket comprises a fixed bracket having the left and right leg portions and the upper wall portion, and a wrapping bracket fixed to the upper surface of the upper wall portion to form the wrapping portion.

[0014] In the seat back frame of the fourth aspect, the left and right legs of the fixed bracket are fixed to the upper frame of the frame body, and the seat belt is wound around the winding bracket fixed to the upper surface of the upper wall of the fixed bracket. In this way, the belt anchor bracket is composed of two parts, the fixed bracket and the winding bracket, which increases the degree of freedom in designing the shape of each part.

[0015] The seat back frame of the fifth aspect is any one of the first to fourth aspects, in which a nut onto which a bolt that fastens and fixes the wrapping bracket to the upper wall portion is threaded is welded to the underside of the upper wall portion, and the upward extension portion faces the nut from the front of the seat back.

[0016] In the seatback frame of the fifth aspect, a nut is welded to the underside of the upper wall portion of the fixing bracket. A bolt that fastens the wraparound bracket to the upper wall portion of the fixing bracket is threaded into this nut. An upward extension formed on the upper end of one of the side frames faces the nut from the front of the seatback. In this way, by arranging the nut and the upward extension side by side in the fore-and-aft direction of the seatback, it is easy to ensure space for arranging the upward extension and the nut.

[0017] The seatback frame of the sixth aspect is any one of the first to fifth aspects, in which the upper frame is inserted into a through hole formed in the upper end of one of the side frames, and the left and right legs of the belt anchor bracket are separated into two on either side of the upper end of the one of the side frames in the left-right direction of the seatback and fixed to the upper frame, respectively.

[0018] In a sixth aspect of the seatback frame, the upper frame of the frame body is inserted into a through-hole formed in the upper end of one of the side frames. The left and right legs of the belt anchor bracket are separated and fixed to the upper frame on both sides of the seat back in the left-right direction relative to the upper end of one of the side frames. As a result, when the upper wall portion spanning between the upper ends of the left and right legs hits the upward extension of one of the side frames due to a load from the belt anchor bracket, the belt anchor bracket is supported in a balanced manner by the upper frame and one of the side frames.

[0019] The vehicle seat of the seventh aspect comprises a seat cushion on which a vehicle occupant sits, a seat back whose skeleton is formed by a seat back frame of any one of the first to sixth aspects and which supports the back of the occupant, and a seat belt device in which a seat belt, which is wound around a retractor attached to the seat back frame, is wound around a winding portion of a belt anchor bracket provided on the seat back frame.

[0020] In the vehicle seat of the seventh aspect, a vehicle occupant sits on a seat cushion, and the occupant's back is supported by a seat back. A retractor of a seat belt device is attached to a seat back frame that forms the framework of the seat back. The seat belt that is wound around the retractor is wound around a winding portion of a belt anchor bracket provided on the seat back frame. The seat back frame is any one of the first to sixth aspects, and therefore the above-mentioned functions and effects can be obtained. [Effects of the Invention]

[0021] As described above, in the seat back frame and vehicle seat according to the present invention, the strength of the belt anchor bracket can be easily ensured. [Brief explanation of the drawings]

[0022] [Figure 1] 1 is a perspective view showing a vehicle seat according to an embodiment; [Figure 2] 1 is a perspective view showing a configuration around a belt anchor bracket in a seat back frame provided in a vehicle seat according to an embodiment. FIG. [Figure 3] FIG. 3 is a first perspective view showing a portion of the configuration shown in FIG. 2. [Figure 4] FIG. 3 is a second perspective view of a portion of the configuration shown in FIG. 2. [Figure 5] FIG. 3 is a front view showing a part of the configuration shown in FIG. 2. [Figure 6] FIG. 3 is a side view showing a part of the configuration shown in FIG. 2. DETAILED DESCRIPTION OF THE INVENTION

[0023] A vehicle seat 10 according to one embodiment of the present invention will be described below with reference to Figures 1 to 6. Note that in each figure, some reference numerals may be omitted to make the drawings easier to understand. Furthermore, arrows FR, LH, RH, and UP, which are appropriately shown in each figure, indicate the front, left, right, and top of the vehicle seat 10, respectively.

[0024] As shown in Fig. 1, a vehicle seat 10 according to an embodiment of the present invention includes a seat cushion 12 on which a vehicle occupant sits, and a seat back 14 that supports the occupant's back. This vehicle seat 10 is, for example, a driver's seat in a right-hand drive vehicle. If this vehicle seat 10 is, for example, a driver's seat in a left-hand drive vehicle, the configuration will be symmetrical to that of this embodiment.

[0025] The framework of the seat back 14 is formed by a seat back frame 20 according to an embodiment of the present invention. When the seat back 14 is in the upright position shown in Fig. 1, the front-rear, left-right, top-bottom directions of the seat back 14 coincide with the front-rear, left-right, top-bottom directions of the vehicle seat 10. Hereinafter, when the front-rear, left-right, top-bottom directions are used in the description, they refer to directions relative to the seat back 14 unless otherwise specified.

[0026] The seatback frame 20 includes a frame main body 22 and a belt anchor bracket 40. The frame main body 22 includes a pair of left and right side frames 24, an upper frame 26 connecting upper ends of the left and right side frames 24 in the left-right direction, a lower frame 28 connecting lower ends of the left and right side frames 24 in the left-right direction, a pair of upper and lower intermediate frames 30, 32 connecting vertically intermediate portions of the left and right side frames 24 in the left-right direction, and a headrest stay 33 fixed to the left-right intermediate portion of the upper frame 26.

[0027] The left and right side frames 24 are elongated plates with their longitudinal direction extending up and down and their thickness direction extending left and right. The upper frame 26, the lower frame 28, and the upper and lower intermediate frames 30, 32 are tubular with their axial direction extending left and right. The left and right side frames 24 are made of, for example, press-formed metal plate material, while the upper frame 26, the lower frame 28, and the upper and lower intermediate frames 30, 32 are made of, for example, metal pipe material.

[0028] The lower ends of the left and right side frames 24 are connected via a well-known reclining mechanism to the rear ends of the seat cushion frame that forms the framework of the seat cushion 12. As a result, the seat back frame 20, i.e., the seat back 14, is connected to the cushion frame, i.e., the seat cushion, so as to be reclining (tilting).

[0029] A retractor 36 of a three-point seat belt device 34 is attached to the upper and lower intermediate frames 30, 32. One longitudinal end of a seat belt (webbing) 38 of the seat belt device 34 is fastened to a winding shaft of the retractor 36, and the other longitudinal end is fastened to an anchor member provided on one of the left and right sides (here, the right side) of the seat cushion 12. A longitudinal intermediate portion of the seat belt 38 is wound around a belt anchor bracket 40 provided on one of the left and right shoulders of the seat back 14. A tongue plate (not shown) is attached to the longitudinal intermediate portion of the seat belt 38 between the anchor member and the belt anchor bracket 40. This tongue plate is connectable to a buckle 42 provided on the other left and right side (here, the left side) of the seat cushion 12.

[0030] In the seat belt device 34 configured as described above, an occupant seated on the seat cushion 12 of the vehicle seat 10 fastens the seat belt 38 by connecting the tongue plate to the buckle 42. In this fastened state, the portion of the seat belt 38 from the belt anchor bracket 40 to the tongue plate serves as a shoulder belt that restrains the upper body of the occupant, and the portion of the seat belt 38 from the tongue plate to the anchor member serves as a lap belt that restrains the waist of the occupant.

[0031] 2, the belt anchor bracket 40 is disposed above one of the left and right side frames 24 (here, the right side frame 24). The belt anchor bracket 40 is composed of, for example, a fixed bracket 46 and a wrapping bracket 50.

[0032] 2 to 6, the fixed bracket 46 is made of, for example, a press-formed metal plate. The fixed bracket 46 has a pair of left and right legs 46A facing each other in the left-right direction and an upper wall 46B spanning the upper ends of the left and right legs 46A, and is generally inverted U-shaped when viewed from the front to back. The left and right legs 46A are fixed to the upper frame 26 of the frame main body 22.

[0033] Specifically, in this embodiment, the right end of the upper frame 26 is inserted into a through-hole 25 formed in the upper end of the right side frame 24, and is fixed to the right side frame 24 by means such as welding. The left and right legs 46A of the fixing bracket 46 are arranged on both left and right sides of the upper end of the right side frame 24. A substantially semicircular cutout 47 (reference numeral omitted except in FIG. 6 ) that is open toward the front of the seat is formed in the lower part of each of the left and right legs 46A. The upper frame 26 is fitted into each cutout 47 from the front side of the seat. The edges of the left and right legs 46A are fixed to the upper frame 26 by means such as welding. An upper wall 46B that spans between the upper ends of the left and right legs 46A faces the upper end of the right side frame 24 from above.

[0034] The wrapping bracket 50 is, for example, composed of a bracket main body 52 and multiple (here, three) wires 54, 56, and 58, forming a wrapping portion around which the seat belt 38 is wrapped. The bracket main body 52 is made of, for example, a press-formed metal plate. The bracket main body 52 has a pair of left and right side wall portions 52A opposing each other in the left-right direction and a lower wall portion 52B spanning the lower ends of the left and right side wall portions 52A, forming a substantially U-shape when viewed in the front-to-rear direction. The three wires 54, 56, and 58 are made of, for example, bent metal wires and spanning the left and right side wall portions 52A. Two of the three wires 54, 56, and 58 are arranged side by side in the front-to-rear direction below the remaining wire 54, and are inclined downward as they extend outward in the left-to-right direction. The longitudinal middle portion of the seat belt 38 is wound around these two wires 56, 58.

[0035] The lower wall portion 52B of the bracket main body 52 is superimposed on the upper surface of the upper wall portion 46B of the fixed bracket 46. The lower wall portion 52B and the upper wall portion 46B each have a plurality of (two in this example) bolt holes (not shown) formed therein. A bolt 60 (see FIG. 2) is inserted into each of these bolt holes from above. Each bolt 60 is threadedly engaged with a plurality of (two in this example) nuts 62 welded to the lower surface of the upper wall portion 46B. This fastens and fixes the bracket main body 52, i.e., the wrap-around bracket 50, to the upper wall portion 46B of the fixed bracket 46.

[0036] The upper wall portion 46B of the fixing bracket 46 is disposed above the right-side side frame 24 (hereinafter, sometimes referred to as the "right side frame 24"). An upward extension portion 24E is formed at the front portion of the upper end of the right side frame 24, protruding upward. The rear portion of the upper end of the right side frame 24, where this upper extension portion 24E is not formed, is recessed downward relative to the front portion of the upper end of the right side frame 24. This upper extension portion 24E is disposed forward of the portions of the left and right legs 46A of the fixing bracket 46 that are fixed to the upper frame 26 (edges of the notches 47), and faces the front portion of the lower surface of the upper wall portion 46B from below, with a gap 64 (reference numeral omitted except in FIG. 5 ). The vertical dimension of this gap 64 is set to, for example, approximately several millimeters.

[0037] As shown in FIG. 4, the right side frame 24 having the upper extension 24E includes a side wall 24A having a thickness in the left-right direction, a front flange 24B extending inward in the left-right direction from the front end of the side wall 24A, and a rear flange 24C extending inward in the left-right direction from the rear end of the side wall 24A. The upper extension 24E is formed by a portion of the side wall 24A and a portion of the front flange 24B, and is generally L-shaped when viewed in the vertical direction. As shown in FIGS. 2 to 5, the upper extension 24E faces from the front one of the two nuts 62 fixed to the underside of the upper wall 46B. In other words, the space behind the upper extension 24E is used as a space for arranging the one nut 62.

[0038] (Action and effect) Next, the operation and effects of this embodiment will be described.

[0039] In this embodiment, the seatback frame 20 that constitutes the framework of the seatback 14 of the vehicle seat 10 includes a frame main body 22 and a belt anchor bracket 40. The frame main body 22 has left and right side frames 24 and an upper frame 26 that spans between the upper ends of the left and right side frames 24. A retractor 36 of a seat belt device 34 is attached to the frame main body 22. Left and right leg portions 46A of a belt anchor bracket 40 are fixed to the upper frame 26 of the frame main body 22. The belt anchor bracket 40 has an upper wall portion 46B that spans between the upper ends of the left and right legs 46A and a winding portion (winding bracket 50) around which the seat belt 38 to be retracted by the retractor 36 is wound, and the upper wall portion 46B faces the upper end of the right side frame 24, which is one of the left and right side frames 24, from above.

[0040] An upper extension 24E is formed at the upper end of the right side frame 24, protruding upward and forward of the fixed portions of the left and right legs 46A of the belt anchor bracket 40 to the upper frame 26. The upper extension 24E faces the lower surface of the upper wall portion 46B of the belt anchor bracket 40 from below. Therefore, when an excessive load from the seat belt 38 acts on the belt anchor bracket 40 during a vehicle collision, the lower surface of the upper wall portion 46B of the belt anchor bracket 40 hits the upper extension 24E, and the load is transmitted to the right side frame 24. This makes it easier to ensure the strength of the belt anchor bracket 40. As a result, measures such as increasing the thickness of the left and right legs 46A or the upper wall portion 46B to ensure the strength of the belt anchor bracket 40 are not necessary, allowing for a reduction in weight and cost of the belt anchor bracket 40.

[0041] Furthermore, in this embodiment, the above-described upward extension 24E faces the underside of the upper wall portion 46B of the belt anchor bracket 40 with a gap 64 therebetween. Therefore, when fixing the left and right legs 46A of the belt anchor bracket 40 to the upper frame 26 of the frame main body 22, it is possible to prevent the upward extension 24E from inadvertently interfering with the underside of the upper wall portion 46B of the belt anchor bracket 40 due to manufacturing variations. This makes it easier to fix the belt anchor bracket 40 to the upper frame 26.

[0042] In this embodiment, the right side frame 24 of the frame main body 22 has a side wall 24A whose thickness direction is in the left-right direction, and a front flange 24B that extends inward in the left-right direction from the front end of the side wall 24A. An upward extension 24E formed at the upper end of the right side frame 24 is composed of a part of the side wall 24A and a part of the front flange 24B, and is generally L-shaped when viewed in the up-down direction. This makes it easier to ensure the strength of the upward extension 24E compared to, for example, a case in which the upward extension 24E is composed of only a part of the side wall 24A or only a part of the front flange 24B.

[0043] In this embodiment, the belt anchor bracket 40 includes a fixed bracket 46 having the left and right leg portions 46A and the upper wall portion 46B, and a wrapping bracket 50 that is fixed to the upper surface of the upper wall portion 46B and forms a wrapping portion for the seat belt 38. In this way, since the belt anchor bracket 40 is made up of two parts, the fixed bracket 46 and the wrapping bracket 50, there is a high degree of freedom in setting the shape of each part.

[0044] In this embodiment, two nuts 62 are welded to the underside of the upper wall portion 46B of the fixed bracket 46. Bolts 60 that fasten and fix the wrapping bracket 50 to the upper wall portion 46B of the fixed bracket 46 are threaded into these nuts 62. An upper extension 24E formed on the upper end portion of the right side frame 24 faces one of the nuts 62 from the front. By arranging the nuts 62 and the upper extension 24E side by side in the front-to-rear direction in this way, it is easy to ensure a space for arranging the nuts 62 and the upper extension 24E.

[0045] In this embodiment, the upper frame 26 of the frame main body 22 is inserted into a through-hole 25 formed in the upper end of the right side frame 24. The left and right leg portions 46A of the belt anchor bracket 40 are separated into two on either side of the seat back in the left-right direction relative to the upper end of the right side frame 24 and are respectively fixed to the upper frame 26. As a result, when the upper wall portion 46B spanning between the upper ends of the left and right legs 46A hits the upward extension portion 24E of the right side frame 24 due to a load from the belt anchor bracket 40 side, the belt anchor bracket 40 is supported in a well-balanced manner by the upper frame 26 and the right side frame 24.

[0046] In the above embodiment, the upper frame 26 is inserted into the through hole 25 formed at the upper end of the right side frame 24 (one of the side frames), but this is not limited to this, and the configuration of the joint between one of the side frames and the upper frame can be changed as appropriate.

[0047] In addition, in the above embodiment, the wrapping bracket 50 is fixed to the fixed bracket 46 using the bolts 60 and nuts 62, but the present invention is not limited to this. For example, the wrapping bracket may be fixed to the fixed bracket by welding.

[0048] Furthermore, in the above embodiment, the belt anchor bracket 40 is described as being made up of two parts, the fixed bracket 46 and the wrapping bracket 50, but this is not limiting, and the belt anchor bracket may also be made up of a single part.

[0049] Furthermore, in the above embodiment, the case where the upward extension 24E is formed by a portion of the side wall portion 24A of the right side frame 24 (one of the side frames) and a portion of the front flange portion 24B was described, but this is not limited to this, and the upward extension may be formed by only a portion of the side wall portion or only a portion of the front flange portion of one of the side frames.

[0050] Furthermore, in the above embodiment, the upper extension portion 24E is configured to face the underside of the upper wall portion 46B of the belt anchor bracket 40 with a gap 64 therebetween, but this is not limited to this, and the configuration may also be such that no gap is formed between the upper extension portion and the upper wall portion of the belt anchor bracket.

[0051] In addition, the present invention can be implemented with various modifications within the scope of the gist thereof. Furthermore, it goes without saying that the scope of the rights of the present invention is not limited to the above-described embodiment. [Explanation of symbols]

[0052] 10 Vehicle seats 12 seat cushions 14 Seat back 20 Seat back frame 22 Frame body 24 Side frame 24A Side wall part 24B Front flange 24E Upper extension 25 through holes 26 Upper frame 34 Seatbelt device 36 Retractor 38 Seatbelt 40 Belt anchor bracket 46 Fixing bracket 46A Legs 46B Upper wall part 50 Winding bracket 60 volts 62 Nut 64 Gap

Claims

1. a frame body having left and right side frames and an upper frame spanning upper ends of the left and right side frames, the frame body having a retractor of a seat belt device attached thereto; a belt anchor bracket having left and right leg portions fixed to the upper frame, an upper wall portion spanning between upper ends of the left and right leg portions facing an upper end portion of one of the left and right side frames from above the seat back, and having a winding portion around which the seat belt to be wound by the retractor is wound; Equipped with an upper end portion of one of the side frames is formed with an upward extension portion that protrudes toward the upper side of the seat back and is located forward of the seat back relative to the fixed portions of the left and right legs to the upper frame and faces the lower surface of the upper wall portion from the lower side of the seat back; The seat back frame has the upward extension portion disposed above the seat back relative to the upper frame.

2. A frame body having left and right side frames and an upper frame spanning between the upper ends of the left and right side frames, to which a retractor of a seat belt device is attached; a belt anchor bracket having left and right leg portions fixed to the upper frame, an upper wall portion spanning between upper ends of the left and right leg portions facing an upper end portion of one of the left and right side frames from above the seat back, and having a winding portion around which the seat belt to be wound by the retractor is wound; Equipped with an upper end portion of one of the side frames is formed with an upward extension portion that protrudes toward the upper side of the seat back and is located forward of the seat back relative to the fixed portions of the left and right legs to the upper frame and faces the lower surface of the upper wall portion from the lower side of the seat back; A seat back frame configured so that when an excessive load from the seat belt acts on the belt anchor bracket, the lower surface of the upper wall portion of the belt anchor bracket comes into contact with the upward extension portion.

3. 3. The seat back frame according to claim 1, wherein the upper extension portion faces the lower surface of the upper wall portion with a gap therebetween.

4. the one side frame has a side wall portion whose thickness direction is the left-right direction of the seat back, and a front flange portion extending inward in the left-right direction of the seat back from a front end portion of the side wall portion, 4. The seat back frame according to claim 1, wherein the upward extension portion is formed by a part of the side wall portion and a part of the front flange portion.

5. The belt anchor bracket is a fixed bracket having the left and right legs and the upper wall; a wrapping bracket fixed to an upper surface of the upper wall portion to form the wrapping portion; The seat back frame according to any one of claims 1 to 4, comprising:

6. A nut having a bolt threaded thereon is welded to the underside of the upper wall portion, the bolt fastening the wrapping bracket to the upper wall portion, The seat back frame according to any one of claims 1 to 4, wherein the upward extension portion faces the nut from the front of the seat back.

7. The upper frame is inserted into a through hole formed in an upper end portion of the one side frame, The seat back frame according to any one of claims 1 to 6, wherein the left and right legs of the belt anchor bracket are separated into two on either side of the seat back in the left-right direction relative to the upper end of one of the side frames and fixed to the upper frame, respectively.

8. A seat cushion on which a vehicle occupant sits; a seat back whose framework is constituted by the seat back frame according to any one of claims 1 to 7 and which supports the back of the occupant; a seat belt device in which a seat belt, which is wound around a retractor attached to the seat back frame, is wound around a winding portion of a belt anchor bracket provided on the seat back frame; A vehicle seat comprising:

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