Vehicle seats

Abstract

To fix a lower connection member to side frames with sufficient strength.SOLUTION: A vehicle seat includes: a seating frame 2 which is a frame of a seating part on which an occupant is seated; and a seat back frame 1 supported by the seating frame 2. The seat back frame 1 includes: side frames SF which are disposed separating from each other in a lateral direction; and a lower connection member 30 which is disposed so as to be spanned between lower parts of the left and right side frames SF and connects the left and right side frames SF. The left and right side frames SF have: side wall parts 12A; and inner extension parts 13 which extend from rear ends of the side wall parts 12A to the inner side in the lateral direction and are positioned separating from each other. The lower connection member 30 has: a front wall part 31 disposed at the occupant side; and a rear wall part 32 connected to the rear side of the front wall part 31. The rear wall part 32 is formed with a through hole 38 into which another member enters, and the through hole 38 overlaps with the front wall part 31 in an anteroposterior direction.SELECTED DRAWING: Figure 6

Description

Technical Field

[0001] The present invention relates to a vehicle seat such as an automotive seat, and more particularly to a vehicle seat that provides improved seating comfort for an occupant during a rear-end collision.

Background Art

[0002] In a so-called rear-end collision, where a vehicle or the like is hit from behind by a following vehicle or collides rearward when traveling backward, the head of a seated occupant tilts rearward due to inertia, and there is a risk that the neck may be subjected to impact.

[0003] Therefore, in order to protect the occupant's head and neck from the impact of a rear-end collision and reduce the impact on the neck, the vehicle seat is provided with a headrest above the seat back that receives the occupant's head from the rear. In order to effectively reduce the impact during a rear-end collision, it is desirable to rapidly reduce the gap between the occupant's head and the headrest at the time of the rear-end collision.

[0004] For this reason, a seat back has been proposed that is configured such that during a rear-end collision, the upper body of the occupant is moved rearward, the load from this movement is received by a pressure receiving member to move the headrest forward, supporting the occupant's head and reducing the impact on the neck (Patent Document 1).

[0005] Further, in the seat back frame of the vehicle seat described in Patent Document 1, the left and right side frames are connected to each other at their lower portions by a plate-shaped lower frame (lower connection member) and a reclining rotation support shaft disposed in front of the lower frame. And as in Patent Document 2, the lower frame may not be a simple plate shape, but may have flanges extending forward at the upper and lower ends. These lower frames are in a substantially vertical posture in a normal seating posture, and are in a posture slightly tilted forward relative to the upper portion of the backrest (the portion against which the upper back of the occupant abuts).

Prior Art Documents

Patent Documents

[0006] [Patent Document 1] Japanese Patent Publication No. 2010-083269 [Patent Document 2] Japanese Patent Publication No. 2008-067723 [Overview of the project] [Problems that the invention aims to solve]

[0007] Incidentally, since the lower connecting member receives the load from the occupants during a rear-end collision, it is desirable that it be fixed to the side frame with sufficient strength.

[0008] This invention was made in view of the above-mentioned background, and aims to fix the lower connecting member to the side frame with sufficient strength. [Means for solving the problem]

[0009] The vehicle seat of the present invention, which solves the aforementioned problems, comprises a seating frame, which is the frame of the seating portion on which the occupant sits, and a seat back frame supported by the seating frame. The seat back frame comprises side frames positioned spaced apart on the left and right, and a lower connecting member positioned between the lower parts of the left and right side frames, connecting the left and right side frames.

[0010] The left and right side frames each have a side wall portion and an inner extension portion that extends inward in the left-right direction from the rear end of the side wall portion and is located apart from each other.

[0011] The lower connecting member has a front wall portion positioned on the occupant side and a rear wall portion connected to the rear of the front wall portion. The rear wall portion has a through-hole into which other members can enter. The through-hole overlaps with the front wall portion in the front-rear direction.

[0012] With this configuration, the lower connecting member can be fixed to the side frame with sufficient strength.

[0013] Further, in the vehicle seat described above, the front wall portion may extend so as to move away from the rear wall portion as the distance from the connecting portion between the front wall portion and the rear wall portion increases.

[0014] Further, in the vehicle seat described above, the seat back frame is configured to be reclinable relative to the seating frame, a shaft connecting the left and right side frames is disposed on the rotation axis of the seat back frame, and the shaft may be positioned between the rear wall portion and the front wall portion.

[0015] Further, in the vehicle seat described above, the shaft may be provided at the position where the interval between the front wall portion and the rear wall portion is the widest.

[0016] Further, in the vehicle seat described above, a bent portion inclined forward may be formed at the distal end portion of the rear wall portion. Effects of the Invention

[0017] According to the present invention, the lower connection member can be fixed to the side frame with sufficient strength. Brief Description of the Drawings

[0018] [Figure 1] It is a perspective view of a vehicle seat. [Figure 2] It is a perspective view of a seat frame. [Figure 3] It is an enlarged perspective view of a lower connection member. [Figure 4] They are views (a) and (b) for explaining the angle of the front surface of the front wall portion. [Figure 5] It is a view of the seat back frame seen from the rear, showing the welded portion between the rear wall portion and the inwardly extending portion. [Figure 6] It is a side cross-sectional view for explaining the mounting structure of the cover on the back surface of the seat back. [Figure 7] It is a side cross-sectional view showing the seat back frame in a normal state. [Figure 8]This is a side sectional view showing the seat back frame at the time of a low-strength rear collision. [Figure 9] This is a side sectional view showing the seat back frame at the time of a high-strength rear collision. [Figure 10] This is a side sectional view of a lower connection member according to a modified example. [Figure 11] This is a perspective view showing a modified example of the relief portion of the lower connection member. [Mode for Carrying Out the Invention]

[0019] Hereinafter, one embodiment of the present invention will be described with reference to the drawings. As shown in Figure 1, a vehicle seat S as an example of the vehicle seat of the present invention is configured to include a seat back S1, a seat cushion portion S2, and a headrest S3. In this specification, the front, rear, left, and right directions are defined based on an occupant seated on the vehicle seat S in a normal state where the seat back S1 is upright (not reclined backward to a supine position).

[0020] A seat frame F as shown in Figure 2 is provided inside the vehicle seat S. The seat frame F is composed of a seat back frame 1 which is the frame of the seat back S1, and a seat cushion frame 2 which is the frame of the seat cushion portion S2. The seat cushion frame 2 and the seat back frame 1 are connected via a reclining mechanism 3 (the detailed structure is not illustrated). A cushion and a skin material are provided on the outer sides of the seat back frame 1 and the seat cushion frame 2, and a cover 5 (see Figure 6) as an example of a member to be attached is attached to the rear surface by a clip 51 as an example of a fixing member, whereby the seat back S1 and the seat cushion portion S2 are configured.

[0021] The seat back frame 1 is constructed in a frame shape by side plates 10 that are spaced apart to the left and right and extend in the vertical direction, an upper frame 21 that connects the upper ends of the side plates 10, and a lower connecting member 30 that connects the lower ends of the left and right side plates 10. The upper frame 21 is made by bending a metal pipe into a U shape and has an upper connecting portion 21A that extends to the left and right, and a connecting portion 21B that extends downward from the left and right ends of the upper connecting portion 21A. The connecting portion 21B is connected to the upper end of the side plate 10 by welding.

[0022] The side plate 10 consists of a lower member 12 made of sheet metal provided at the lower end and an upper member 11 which is integrally welded to the upper part of the lower member 12. The lower member 12 comprises a side wall portion 12A and an inner extension portion 13 which extends inward from the rear end of the side wall portion 12A.

[0023] As shown in Figure 5, the inner extension portion 13 has an inclined edge portion 13A that is inclined at an angle γ with respect to the vertical, such that the inner end moves from the inside to the outside as it goes from top to bottom. This inclined edge portion 13A is the part to be welded to the lower connecting member 30 and the inner extension portion 13, as will be described later. The inner extension portion 13 also has a clip hole 13B, which is an example of a mounting hole into which a clip 51 for attaching the cover 5 on the back of the seat back S1 is inserted.

[0024] Returning to Figure 2, the side frame SF of the seat back frame 1 is composed of a side plate 10 and a connection portion 21B of the upper frame 21. A pressure-receiving member 40 made of plate-shaped resin is positioned between the left and right side frames SF, and the pressure-receiving member 40 is connected to the left and right side frames SF at two points, upper and lower, via connecting wires (connecting members) 41 made of springy, bent wires. Specifically, the end of the upper connecting wire 41 is engaged with a bracket 43 welded to the connection portion 21B, and the lower connecting wire 41 is connected at its lower end to a pivotable member 45 that can swing back and forth. The pivotable member 45 is fixed to the side plate 10 (upper member 11), and as disclosed in Japanese Patent Application Publication No. 2010-179748, for example, the lower end of the arm is normally located forward, but when a large force is applied from the connecting wire 41 toward the rear, the lower end swings backward, allowing the pressure-receiving member 40 to move significantly backward.

[0025] The upper frame 21 is provided with a pillar support portion 23, and a headrest frame (not shown) is provided on the pillar support portion 23. The headrest S3 described above is formed by providing a cushioning member on the outside of the headrest frame.

[0026] Next, the lower connecting member 30 will be described in detail. The lower connecting member 30 is positioned to span between the lower parts of the left and right side frames SF. This suppresses the lateral deformation of the seat frame F even when subjected to load from the side, and allows the load from the side to be transmitted to the center of the vehicle.

[0027] The lower connecting member 30 is made of sheet metal and, as shown in Figure 3, comprises a front wall portion 31, a rear wall portion 32, an upper wall portion 33 extending rearward from the upper end of the front wall portion 31 and connecting the front wall portion 31 and the rear wall portion 32, a lower flange 34, and a folded flange 35.

[0028] The front wall portion 31 is located in front of the shaft 3S of the reclining mechanism 3. The shaft 3S is positioned on the pivot axis between the seat frame 2 and the seat back frame 1, and is provided to connect the left and right side frames SF to support the rotation by the reclining mechanism 3. Because the front wall portion 31 of the lower connecting member 30 is located in front of the shaft 3S, the load applied from the occupant's buttocks, etc., via the seat back cushion does not directly apply to the shaft 3S, but rather to the front wall portion 31, thereby mitigating the feeling of pressure from the shaft 3S on the occupant's buttocks, etc.

[0029] As shown in Figure 4(a), the front surface 31A of the front wall portion 31 is angled in a side view to be parallel to or upward relative to the direction in which the connecting portion 21B extends (straight line L1). In the example in Figure 4(a), the front surface 31A is angled upward at an angle α with respect to the straight line L1. The front wall portion 31 is also angled upward at an angle β with respect to the rear wall portion 32. As a result, the front wall portion 31 and the rear wall portion 32 are connected at their upper ends and form a shape that opens downward, thus ensuring a stroke for the front wall portion 31 to deform backward during a rear collision. Note that the connecting portion 21B, which is a pipe constituting the side frame SF, is not straight in a side view, but may be curved so that the upper part is upright, or conversely, curved so that the upper part is flat, as shown in Figure 4(b). In such cases, the angle of the front surface 31A with respect to the pipe (connecting portion 21B) refers to the angle with respect to the most upright direction of the pipe.

[0030] The lower end of the front wall portion 31 extends below the lower end of the rear wall portion 32. This allows the front wall portion 31 to be made larger, reducing the feeling of contact between the occupant and the lower connecting member 30, and the longer length from the upper end to the lower end of the front wall portion 31 makes it easier to deform the front wall portion 31 backward during a rear collision.

[0031] The rear wall portion 32 is a wall connected to the side frame SF (inner extension portion 13), and is a member that connects and supports the lower connecting member 30 to the side frame SF. Specifically, as shown in Figure 4(a), the rear surface of the rear wall portion 32 is aligned with the front surface of the inner extension portion 13, and as shown in Figure 5, the inner extension portion 13 and the rear wall portion 32 are welded along the inclined edge portion 13A of the inner extension portion 13. Since the inclined edge portion 13A is oblique to the vertical direction, even if there is little overlap between the inclined edge portion 13A and the rear wall portion 32 in the height direction, the welding length can be increased to maintain the required welding strength. The angle γ of the inclined edge portion 13A is preferably 20 degrees or more. An angle γ of 20 degrees or more greatly increases the effect of increasing the welding length. The angle γ is more preferably 30 degrees or more, and even more preferably 40 degrees or more. Furthermore, by setting the angle γ to 70 degrees or less, it is possible to prevent the inner extension portion 13 from becoming excessively acute. Furthermore, because the rear wall portion 32 is fixed to the side frame SF, the rearward movement of the rear wall portion 32 is suppressed during a rearward collision, and the connection between the front wall portion 31 and the rear wall portion 32 becomes more easily deformable, making it easier to control the rearward movement of the front wall portion 31.

[0032] As described above, the lower connecting member 30 of this embodiment has a front wall portion 31 and a rear wall portion 32 connected to the front wall portion 31. Therefore, compared to a simple plate-shaped lower connecting member, it has higher rigidity against crushing in the left-right direction and can efficiently transmit loads from the sides to the center of the vehicle.

[0033] As shown in Figure 3, the upper wall portion 33 has a flat plate shape that extends approximately in the front-to-back direction. This allows the upper end of the front wall portion 31 and the upper end of the rear wall portion 32 to be appropriately separated in the front-to-back direction, and when the front wall portion 31 deforms backward, the deformation stroke can be increased. Furthermore, the connection between the front wall portion 31 and the upper wall portion 33 has a smooth, edgeless shape due to the natural R shape created when the upper wall portion 33 and the front wall portion 31 are bent.

[0034] The lower flange 34 is bent backward from the lower end of the front wall portion 31 below the shaft 3S and extends backward. The connection between the front wall portion 31 and the lower flange 34 also has a smooth, edgeless shape due to the natural R shape created when the lower flange 34 and the front wall portion 31 are bent. Furthermore, the lower flange 34 does not connect to the rear wall portion 32, and as a result the lower connecting member 30 does not have a closed cross-sectional shape. In this way, the lower flange 34 and the rear wall portion 32 are not connected, and there is a gap between them, which makes it easy for the front wall portion 31 to deform backward.

[0035] The folded flange 35 is formed by folding forward from the rear end of the lower flange 34 on the lower side, and the front end of the folded flange 35 is located behind the lower end of the front wall portion 31. In this way, the lower connecting member 30 is equipped with the lower flange 34 and the folded flange 35, which increases the cross-sectional area of ​​the lower connecting member 30. As a result, rigidity in the left-right direction is improved, and load transmission to the side is improved. In addition, because the front end of the folded flange 35 is located behind the lower end of the front wall portion 31 (the part where the front wall portion 31 and the lower flange 34 are connected), in the event of a rear collision, the edge of the front end of the folded flange 35 will not strongly hit the seat back cushion, thereby reducing the feeling of contact between the lower connecting member 30 and the occupant, and also reducing damage to the seat back cushion.

[0036] The rear wall portion 32 of the lower connecting member 30, more specifically from the rear wall portion 32 to the upper wall portion 33, has through holes 38 formed in two locations on the left and right. As shown in Figure 6, the through holes 38 function as relief portions to prevent the tip of the clip 51 from interfering with the rear wall portion 32 of the lower connecting member 30 when the rear cover 5 is attached to the clip hole 13B with the clip 51. For this reason, the through holes 38 are provided at positions corresponding to each clip hole 13B.

[0037] As shown in Figure 5, the lower connecting member 30 does not reach the side wall portion 12A, and a small gap is provided between it and the side wall portion 12A. However, if manufacturing tolerances of the lower connecting member 30 or the lower connecting member 30 riding up onto the corner of the lower member 12 are not a problem, the lower connecting member 30 may be configured so that both ends abut against the side wall portion 12A.

[0038] The function of the vehicle seat S, configured as described above, during a rear-end collision will now be explained. As shown in Figure 7, before the rear collision occurs, the rotating member 45 is in a position where its lower end is swung forward, and the pressure-receiving member 40 is in the foremost position within its range of motion. Although the rotating member 45 is not shown in Figures 7 to 9, in the normal state shown in Figure 7, the lower end of the rotating member 45 is located forward.

[0039] In the event of a relatively minor rear collision, as shown in Figure 8, the central part of the seatback cushion 50 (the part where the occupant P's back rests) moves backward, and the seatback cushion 50 pushes the pressure-receiving member 40 backward, causing the pressure-receiving member 40 to move backward. At this time, the lower end of the rotating member 45 swings backward. Also, the lower part of the seatback cushion 50 (the part where the occupant P's buttocks, etc., rest) deforms slightly when its inner surface comes into contact with the front surface 31A of the lower connecting member 30. However, since the front surface 31A has a wide surface and is slightly inclined upward relative to the connecting part 21B and the rear wall part 32, the reaction force received by the occupant P's buttocks, etc., from the lower connecting member 30 acts as a small pressure, and the feeling of contact with the lower connecting member 30 on the occupant P is soft. Furthermore, since the connection between the front wall portion 31 and the upper wall portion 33 of the lower connecting member 30, and the connection between the front wall portion 31 and the lower flange 34, are gently curved surfaces, the occupant P will not feel a strong impact from the lower connecting member 30. In addition, since the front end of the folded flange 35 is located behind the lower end of the front wall portion 31, the edge of the front end of the folded flange 35 will not strongly contact the inner surface of the seat back cushion 50, thereby suppressing damage to the seat back cushion 50. Also, since the front wall portion 31 is located in front of the shaft 3S, the seat back cushion 50 does not directly contact the shaft 3S. Therefore, the occupant P will not feel any impact from the shaft 3S.

[0040] In the event of a relatively strong rearward collision, as shown in Figure 9, the central part of the seat back cushion 50 moves significantly backward, and consequently, the pressure receiving member 40 also moves significantly backward as the connecting wire 41 undergoes elastic deformation. At this time, the seat back cushion 50 strongly strikes the front surface 31A of the lower connecting member 30, and the lower connecting member 30 bends and deforms at the connection point between the front wall portion 31, including the upper wall portion 33, and the rear wall portion 32. Therefore, even if a strong force is applied to the seat back cushion 50 from the occupant P's buttocks, the front wall portion 31 of the lower connecting member 30 moves backward to absorb the impact, and the occupant P does not feel a strong impact on their buttocks. In particular, in the vehicle seat S of this embodiment, there is a flat upper wall portion 33 that extends substantially in the front-rear direction between the front wall portion 31 and the rear wall portion 32, so a space is secured between the front wall portion 31 and the rear wall portion 32, and the stroke of the rearward deformation of the front wall portion 31, that is, the amount of impact absorbed, can be increased.

[0041] Furthermore, as in the case of a minor rear-end collision, the connection between the front wall portion 31 and the upper wall portion 33 of the lower connecting member 30, and the connection between the front wall portion 31 and the lower flange 34, are gently curved surfaces, so the occupant P is less likely to feel a strong impact from the lower connecting member 30. In addition, since the front end of the folded flange 35 is located behind the lower end of the front wall portion 31, the edge of the front end of the folded flange 35 does not strongly contact the inner surface of the seat back cushion 50, thereby suppressing damage to the seat back cushion 50. Moreover, since the front wall portion 31 is located in front of the shaft 3S, the seat back cushion 50 does not directly contact the shaft 3S, thereby mitigating the impact of the shaft 3S on the occupant P.

[0042] Furthermore, in the vehicle seat S of this embodiment, the lower connecting member 30 is not a flat plate as in the conventional design, but has a front wall portion 31 and a rear wall portion 32 that are connected to each other at the top, thus improving the overall rigidity against bending loads in the longitudinal direction. For this reason, in the conventional design, during a rear collision, the center of the lower frame would be displaced rearward relative to the side frame, bending into a V-shape in plan view, and consequently the side frame would deform (change direction) so that its front end moved inward on both sides. However, in the vehicle seat S of this embodiment, such deformation is less likely to occur. In other words, the lower connecting member 30 is prone to deformation such that the front wall portion 31 moves closer to the rear wall portion 32, but as a whole, it is less prone to deformation such as bending into a V-shape in plan view, thus suppressing deformation of the side frame SF. In addition, since the lower connecting member 30 is provided to span across the left and right side frames SF, when a load is applied that causes the side frame SF to deform inward, the front wall portion 31 contacts the inner surface of the side frame SF, thereby suppressing deformation of the side frame SF.

[0043] Furthermore, in the vehicle seat S of this embodiment, the lower connecting member 30 is positioned to span the left and right side frames SF, and has a sufficient cross-sectional area provided by the front wall portion 31, rear wall portion 32, upper wall portion 33, lower flange 34, and folded flange 35. Therefore, when the vehicle receives a collision load from the side, it suppresses the lateral deformation of the vehicle seat S and can transmit the load from the side to the center of the vehicle. In particular, since the lower connecting member 30 is welded to the inner extension portion 13 of the side frame SF at the inclined edge portion 13A, it is fixed to the side frame SF with sufficient strength due to the long weld length. This increases the rigidity of the seat back frame 1 and allows for efficient transmission of the load from the side to the center of the vehicle. In other words, the lateral rigidity of the vehicle seat S can be increased by increasing the weld length between the lower connecting member 30 and the inner extension portion 13 without increasing the vertical size of the lower connecting member 30.

[0044] Furthermore, in the vehicle seat S of this embodiment, the rear wall portion 32 of the lower connecting member 30 has a through hole 38 as a relief portion, which prevents interference between the clip 51 and the rear wall portion 32 when attaching the cover 5 on the back of the seat back S1, making assembly easier. In other words, even if there are some errors in the size and shape of the rear wall portion 32, interference between the clip 51 and the rear wall portion 32 can be avoided, so there is no need to pay excessive attention to the assembly of the lower connecting member 30 and the side frame SF or the attachment of the clip 51, making the work easier. In addition, since the relief portion is a through hole 38, when manufacturing the lower connecting member 30 made of sheet metal by press working, the relief portion can be easily formed by blanking, making manufacturing easier.

[0045] Although embodiments of the present invention have been described above, the present invention can be implemented by modifying it as appropriate, as shown in the following other embodiments.

[0046] For example, in the above embodiment, the lower connecting member 30 had a flat upper wall portion 33, but the upper wall portion 33' connecting the front wall portion 31 and the rear wall portion 32 may be bent with a single radius, as shown in Figure 10.

[0047] Furthermore, in the above embodiment, the relief portion of the lower connecting member 30 is formed by a through hole 38, but as shown in Figure 11, it may also be formed by a recess 38'. By using a recess 38' instead of a through hole 38, the relief portion can be formed without reducing the strength of the rear wall portion 32, and interference between the clip 51 and the rear wall portion 32 can be avoided.

[0048] In the above embodiment, the front surface 31A of the front wall portion 31 was angled upward in a side view relative to the direction in which the pipe of the connecting portion 21B extends, but it may also be parallel to the direction in which the pipe extends.

[0049] In the above embodiment, a pressure-receiving member 40 is provided to actively draw the occupant P into the seat back S1 during a rear collision. However, the present invention may also be applied to a seat without a pressure-receiving member 40. In any case, the presence of the pressure-receiving member 40 makes it easier for the lower connecting member 30 and the occupant P to come into contact, so the present invention can be effectively utilized in such cases.

[0050] In the above embodiment, the inclined edge portion 13A of the inner extension portion 13 was inclined with respect to the vertical direction such that the inner end moves from the inside to the outside as it goes from top to bottom. However, conversely, the inner end may be inclined with respect to the vertical direction such that it moves from the outside to the inside as it goes from top to bottom.

[0051] In the above embodiment, the pressure-receiving member 40 was supported on the side frame SF by a connecting wire 41, but it can also be supported on the side frame SF by other connecting members such as rubber or a belt.

[0052] In the above embodiment, the seat back cover was given as an example of a component to be mounted, but harnesses, switches operated from the rear seats, and pockets on the back of the seat back can also be mounted. Furthermore, the mounting holes are not just holes, but can also be holes for screwing in tapping bolts or female threaded holes, and the fixing members can be bolts, tapping bolts, rivets, etc.

[0053] Furthermore, although the above embodiment showed a vehicle seat S as an example of application for vehicle seats, the vehicle seat of the present invention can also be applied to other vehicle seats, such as seats for ships or aircraft. [Explanation of Symbols]

[0054] 1. Seat back frame 2. Seating Frame 3. Reclining mechanism 3S shaft 5 Cover 10 Side Plates 11 Upper Member 12 Lower Members 12A Side wall part 13 Inner extension 13A Inclined edge 13B Clip Hole 21 Upper frame 21A Upper connection part 21B Connection section 23 Pillar support section 30 Lower connecting member 31 Front wall 31A Front 32 Rear wall 33 Upper wall 33′ Upper wall 34 Lower flange 35 Folded flange 38 Through holes 38′ recess 40 Pressure-receiving member 50 Seat Back Cushion 51 clips F Seat Frame S Vehicle Seat S1 Seatback S2 seating area S3 Headrest SF Side Frame

Claims

[Claim 1] A seat back frame supported by a seat frame, which is the frame of the seating area where the occupant sits, The seat back frame comprises side frames spaced apart to the left and right, and a lower connecting member positioned between the lower parts of the left and right side frames, connecting the left and right side frames. The seat back frame comprises a shaft positioned on the pivot axis of the seat frame relative to the seating frame, and includes a shaft connecting the left and right side frames, The lower connecting member is made of sheet metal and comprises a front wall portion located on the occupant side, which receives the load from the occupant's buttocks during a rear collision; a rear wall portion connected to the rear of the front wall portion and connected to the side frame; and a connecting portion that connects the front wall portion and the rear wall portion. The rear wall portion has a recessed shape on its front surface due to its lower end being bent forward. The front wall portion has a shape in which the rear surface is recessed. A seat back frame characterized in that the recessed shape on the rear surface of the front wall portion and the recessed shape on the front surface of the rear wall portion are opposite each other with the shaft in between.

Images