seat frame

Abstract

This reduces the molding cost of the lower frame while suppressing deformation of the reclining rod. [Solution] The seat frame 1 comprises a back frame 2 having a lower frame 22 and an elastic member 3, a cushion frame 4, a pair of reclining units 5, and a reclining rod 6 located in front of the lower frame 22 and connecting a pair of reclining rods. The elastic member 3 comprises a main body portion 31 that extends between the lower frame 22 and the reclining rod 6 in the front-rear direction of the seat, and a bent portion 32 that bends and extends from the first end in the extension direction of the main body portion 31 and is connected to the lower frame 22.

Description

Technical Field

[0001] The present disclosure relates to a seat frame.

Background Art

[0002] Patent Document 1 describes a seat frame used for a vehicle seat. The seat frame includes a back frame having a lower frame, a pair of reclining units, and a reclining rod connecting the pair of reclining units.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The lower frame of the seat frame extends by bending from behind the reclining rod, passing under the reclining rod, and reaching in front of the reclining rod. Therefore, for example, when a vehicle equipped with a vehicle seat is rear-ended and the seated person is pressed against the seat back, the front end side of the lower frame receives an external force from the seated person in the direction from the front to the back. Therefore, it is possible to suppress the reclining rod from receiving an external force in this direction from the seated person and deforming into a shape in which the central portion of the reclining rod protrudes backward (hereinafter, simply referred to as deforming). However, since the shape of such a lower frame is complicated, there is a possibility that the cost for forming the lower frame increases.

[0005] In one aspect of the present disclosure, it is desirable to reduce the cost of forming the lower frame while suppressing deformation of the reclining rod.

Means for Solving the Problems

[0006] One aspect of the present disclosure is a seat frame (1) used in a vehicle seat, comprising a cushion frame (4), a back frame (2), a pair of reclining units (5), and a reclining rod (6). The cushion frame (4) constitutes the skeleton of the seat cushion of the vehicle seat. The back frame (2) is a member that constitutes the skeleton of the seat back of the vehicle seat. The back frame (2) comprises a pair of side frames (21), a lower frame (22), and an elastic member (3). The pair of side frames (21) are arranged on both sides in the seat width direction and extend in an extension direction perpendicular to the seat width direction. The first end (D1) of the pair of side frames (21) in the extension direction is rotatably connected to the rear end of the cushion frame in the seat front-rear direction about an axis extending in the seat width direction. The lower frame (22) extends in the seat width direction and connects the first end (D1) of the pair of side frames (21). The elastic member (3) is positioned between a pair of side frames (21) in the seat width direction, is elongated in the extension direction, and is elastic. A pair of reclining units (5) are positioned at the first end (D1) of each of the pair of side frames (21), and are configured to lock and unlock the angle of the pair of side frames (21) relative to the cushion frame (4). The reclining rod (6) extends in the seat width direction and connects the pair of reclining units (5) together. The normal state is when the angle of the pair of side frames (21) relative to the cushion frame (4) is such that the extension direction is approximately the same as the vertical direction of the seat. In the normal state, the reclining rod (6) is positioned in front of the lower frame (22) in the seat front-rear direction. The elastic member (3) comprises a main body (31) and a bending portion (32). The main body (31) extends in the extension direction so as to pass between the lower frame (22) and the reclining rod (6) in the front-rear direction of the seat in its normal state. The bent portion (32) bends and extends from the first end (D1) in the extension direction of the main body (31) and is connected to the lower frame (22).

[0007] With the above configuration, under normal conditions, when an external force is applied to the reclining rod in a forward-to-backward direction, the reclining rod comes into contact with the main body of the elastic member, and the external force is absorbed by the elastic deformation of the elastic member. Therefore, deformation of the reclining rod due to the external force can be suppressed. In addition, the cost of molding the lower frame can be reduced compared to the case where the lower frame bends and extends in front of the reclining rod.

[0008] In one aspect of this disclosure, the elastic member (3) may be a linear member. With the above configuration, deformation of the reclining rod can be effectively suppressed. In one aspect of the present disclosure, the bent portion (32) may include a folded portion (34) and a connecting portion (33). The folded portion (34) extends in the extension direction and is connected to the lower frame (22). The connecting portion (33) connects the ends of the folded portion (34) and the main body portion (31) at the first end side (D1) in the extension direction.

[0009] With the above configuration, deformation of the reclining rod can be effectively suppressed. In one aspect of the present disclosure, the connecting portion (33) may extend from the first end (D1) in the stretching direction of the main body portion (31) to the first end (D1) in the stretching direction of the folded portion (34), in a direction substantially coincided with the sheet width direction and the thickness direction perpendicular to the stretching direction.

[0010] With the above configuration, when the elastic member receives an external force from the reclining rod in the direction from front to rear in the seat's longitudinal direction, the displacement of the main body of the elastic member toward the rear can be suppressed. Therefore, deformation of the reclining rod can be effectively suppressed. [Brief explanation of the drawing]

[0011] [Figure 1] This is a perspective view of the seat frame. [Figure 2]This is a cross-sectional view perpendicular to the left-right direction around the bent portion of the elastic member in the seat frame. [Modes for carrying out the invention]

[0012] Hereinafter, exemplary embodiments of the present disclosure will be described with reference to the drawings. [1. Overview] The seat frame 1 of this embodiment is used, for example, as a seat for a vehicle (see Figures 1 and 2). The vehicle seat is used, for example, as a seat in a passenger car. The directions in the following description and in each drawing refer to the directions when the vehicle seat is assembled in a vehicle (i.e., a passenger car). In this embodiment, the vehicle seat is assembled, for example, such that the seat width direction coincides with the left-right direction of the vehicle, the seat height direction coincides with the up-down direction of the vehicle, and the seat front-rear direction coincides with the front-rear direction of the vehicle. Hereafter, the left-right direction, the up-down direction, and the front-rear direction of the vehicle will be simply referred to as the left-right direction, the up-down direction, and the front-rear direction, respectively. In addition, the side of the seat frame 1 where the left-right ends are located relative to the center in the left-right direction is referred to as the outside, and the side opposite the outside is referred to as the inside.

[0013] The seat frame 1 comprises a back frame 2, a cushion frame 4, a pair of reclining units 5, and a reclining rod 6 (see Figure 1). The back frame 2 constitutes the skeleton of the seat back. The seat back is the part of the vehicle seat that supports the back of the occupant. The cushion frame 4 constitutes the skeleton of the seat cushion. The seat cushion is the part of the vehicle seat that supports the buttocks of the occupant.

[0014] <Back frame> The back frame 2 comprises a pair of side frames 21, a lower frame 22, an upper frame 23, and two elastic members 3 (see Figures 1 and 2).

[0015] A pair of side frames 21 are positioned on both sides in the left-right direction and extend in an extension direction perpendicular to the left-right direction. Hereafter, one side in the extension direction will be referred to as the first end D1, and the side opposite the first end D1 will be referred to as the second end D2. The first end D1 in the extension direction of each side frame 21 is rotatably connected by a hinge pin 51, which will be described later, to the rear end of each lower arm 41 of the cushion frame 4, which will be described later, about an axis extending in the left-right direction.

[0016] Hereafter, the normal state will be defined as the condition in which the angle of the pair of side frames 21 relative to the cushion frame 4 is such that the extension direction is approximately the same as the vertical direction. The direction perpendicular to the left-right direction and the extension direction will be defined as the thickness direction, with one side in the thickness direction being defined as the front side T1 and the opposite side of the front side T1 being defined as the back side T2. In the normal state, the end of the front side T1 of the side frame 21 is located in front of the end of the back side T2.

[0017] The portion of the pair of side frames 21 near the center in the extension direction, specifically the portion on the second end side D2, curves toward the back side T2 as it moves from the first end side D1 towards the second end side D2. Each of the pair of side frames 21 comprises a plate-like portion 211, a front wall portion 212, and a back wall portion 213. The pair of plate-like portions 211 extend in the extension direction and face each other in the left-right direction. The portion of each plate-like portion 211 at the second end D2, relative to the center in the extension direction, has a shorter length in the thickness direction (i.e., the width of the plate-like portion 211) as it approaches the second end D2. A through hole is provided at the first end D1 in the extension direction of each plate-like portion 211, penetrating the plate-like portion 211 in the left-right direction.

[0018] The front wall portion 212 is a plate-like portion that protrudes inward from the end of the front side T1 of each plate-like portion 211. The back wall portion 213 is a plate-like portion that protrudes inward from the end of the back side T2 of each plate-like portion 211. The front wall portion 212 and the back wall portion 213 of each side frame 21 face each other in the thickness direction.

[0019] The lower frame 22 is a plate-like member. The lower frame 22 is formed, for example, by performing press forming on a flat metal plate. The lower frame 22 includes a plate-like portion 221 that extends longitudinally in the left-right direction and spreads in the extending direction. Both ends of the plate-like portion 221 in the left-right direction are respectively connected to the back wall portions 213 of the pair of side frames 21. The end portion of the first end side D1 of the lower frame 22 is located on the rear side and the lower side with respect to the reclining rod 6 described later in the normal state.

[0020] The upper frame 23 extends in the left-right direction and connects the second end sides D2 of the pair of side frames 21 to each other. The two elastic members 3 are members that are supported by the side frames 21 and the lower frame 22 and receive an external force from the back of the seated person (see FIGS. 1 and 2). Each elastic member 3 is composed of an elongated member having elasticity. Each elastic member 3 of the present embodiment is composed of a linear material having a circular cross-sectional shape (specifically, a metal wire). However, it is not limited thereto, and each elastic member 3 may be composed of, for example, an elongated leaf spring or the like.

[0021] The two elastic members 3 are arranged between the pair of side frames 21 in the left-right direction and extend longitudinally in the extending direction. The two elastic members 3 are respectively arranged on both sides in the left-right direction and have a bilaterally symmetric shape. Each elastic member 3 includes a main body portion 31 and a bent portion 32 (see FIGS. 1 and 2).

[0022] The main body portion 31 extends in the extension direction. The first end D1 of the main body portion 31 is located on the front side T1 with respect to the lower frame 22. The portion of the main body portion 31 from near the center in the extension direction to the second end D2 bends multiple times so as it approaches the second end D2, it curves outward. The end of the second end D2 of the main body portion 31 curves outward, and the outer circumferential surface of this end abuts against and is joined to the front side T1 surface of the back wall portion 213 of the side frame 21. Specifically, the end of the second end D2 of the main body portion 31 has a flat shape with first and second surfaces facing each other in the thickness direction, and the second surface located on the back side T2 abuts against the front side T1 surface of the back wall portion 213 of the side frame 21 and is joined by welding or the like.

[0023] Furthermore, in its normal state, the main body 31 extends in an extending direction so as to pass between the lower frame 22 and the reclining rod 6 (described later) in the front-rear direction (see Figure 2). That is, in its normal state, the end of the first end D1 of the main body 31 is located behind and below the reclining rod 6 (described later). There is a gap between the main body 31 and the reclining rod 6.

[0024] The bent portion 32 extends from the end of the first end D1 of the main body portion 31 toward the back side T2, and is connected to the lower frame 22. The bent portion 32 includes a connecting portion 33 and a folded portion 34 (see Figure 2).

[0025] The connecting portion 33 extends from the end of the first end D1 of the main body portion 31 toward the back side T2, in a direction that is approximately consistent with the thickness direction. In the normal state, the connecting portion 33 is located behind and below the reclining rod 6, which will be described later.

[0026] The folded portion 34 extends in the extension direction from the end of the connecting portion 33 opposite to the main body portion 31 (i.e., the back side T2) toward the second end side D2. In other words, the connecting portion 33 connects the ends of the main body portion 31 and the folded portion 34 toward the first end side D1.

[0027] The outer circumferential surface of the folded portion 34 abuts against the front surface T1 of the plate-shaped portion 221 of the lower frame 22 and is joined by welding or the like over its entire length. The portion of the folded portion 34 at the second end D2 has a flat shape with first and second surfaces facing each other in the thickness direction, and the second surface located on the back side T2 abuts against the front surface T1 of the plate-shaped portion 221 of the lower frame 22 and is joined by welding or the like.

[0028] <Cushion frame> The cushion frame 4 comprises a pair of lower arms 41, first and second rods 42 and 43, a front panel 44, and cushion wires 45 (see Figure 1).

[0029] The pair of lower arms 41 are positioned on both sides of the cushion frame 4 in the left-right direction and are members that extend in the front-rear direction. The rear end of each lower arm 41 is positioned outward relative to the first end D1 of each side frame 21.

[0030] Each lower arm 41 has a through hole at its rear end that penetrates it in the left-right direction. The through hole in the lower arm 41 overlaps with the through hole in the side frame 21. The first rod 42 is a cylindrical member positioned at the front end of the cushion frame 4 and extending in the left-right direction. The first rod 42 is rotatably connected to the front end of a pair of lower arms 41. The first rod 42 is also fixed to a pair of front lifter links 71, which will be described later.

[0031] The second rod 43 is a cylindrical member positioned at the rear end of the cushion frame 4 and extending in the left-right direction. The second rod 43 is rotatably connected to the rear ends of a pair of lower arms 41 and is fixed to a pair of rear lifter links 72, which will be described later.

[0032] The front panel 44 is a plate-shaped member positioned at the front end of the cushion frame 4. Both ends of the front panel 44 in the left-right direction are connected to the front ends of a pair of lower arms 41.

[0033] The cushion wire 45 is supported by the first and second rods 42 and 43 and is a member that receives external forces from the seated person's buttocks. The cushion wire 45 is positioned between a pair of lower arms 41 in the left-right direction and between the first and second rods 42 and 43 in the front-rear direction. The cushion wire 45 is composed of a plurality of wire members as an example. In this embodiment, the cushion wire 45 is composed of a plurality (two in this embodiment) of first wires that extend in the front-rear direction and are connected to the first and second rods 42 and 43 at both ends, and a plurality (three in this embodiment) of second wires that extend in the left-right direction and are connected to the plurality of first wires.

[0034] <Reclining Unit> The pair of reclining units 5 are configured to allow locking and unlocking of the angle of the pair of side frames 21 relative to the cushion frame 4 (in other words, the angle of the back frame 2) (see Figure 1). Each reclining unit 5 is positioned between the first end D1 of each side frame 21 and the rear end of each lower arm 41 in the left-right direction.

[0035] Each reclining unit 5 is equipped with a hinge pin 51. The hinge pin 51 is a shaft member extending in the left-right direction and is inserted into the through-holes of the lower arm 41 and the side frame 21. That is, the hinge pin 51 rotatably connects the first end D1 of each side frame 21 to the rear end of each lower arm 41 about an axis extending in the left-right direction. The inner end of the hinge pin 51 is positioned inside the plate-shaped portion 211 of the side frame 21, and the outer end of the hinge pin 51 is positioned outside the lower arm 41.

[0036] The hinge pin 51 includes a cylindrical portion 511 that extends in the left-right direction. The cylindrical portion 511 is located inside the plate-shaped portion 211 of the side frame 21 and has an opening at its inner end. <Reclining Rod> The reclining rod 6 is a pipe-shaped member that extends in the left-right direction (see Figures 1 and 2). Both ends of the reclining rod 6 are inserted into the interior of each hinge pin 51 through the opening of the cylindrical portion 511 and joined to each hinge pin 51 by welding or the like. In other words, the reclining rod 6 connects the hinge pins 51 of the pair of reclining units 5.

[0037] In its normal state, the reclining rod 6 is positioned forward relative to the lower frame 22. <Displacement mechanism of the cushion frame> Furthermore, the seat frame 1 of this embodiment includes a pair of front lifter links 71, a pair of rear lifter links 72, a sector gear 73, a pair of slide rails 74, and a slide lever 75 (see Figure 1). The pair of front lifter links 71, the pair of rear lifter links 72, and the sector gear 73 are components for displacing the cushion frame 4 in the vertical direction.

[0038] A pair of front lifter links 71 are positioned on both sides in the left-right direction and extend longitudinally. The first end of each of the pair of front lifter links 71 is rotatably connected to the front end of each upper rail 74B of the pair of slide rails 74, which will be described later. The second ends of the pair of front lifter links 71 are fixed near both ends of the first rod 42.

[0039] A pair of rear lifter links 72 are positioned on each side in the left-right direction and extend longitudinally. Each rear lifter link 72 is located behind the front lifter link 71. The first end of each of the pair of rear lifter links 72 is rotatably connected to the rear end of each upper rail 74B of the pair of slide rails 74, which will be described later. The second end of each of the pair of rear lifter links 72 is fixed near both ends of the second rod 43.

[0040] The sector gear 73 is a component fixed to the right rear lifter link 72. As the sector gear 73 rotates around the axis of the second rod 43, the rear lifter link 72 to which the sector gear 73 is fixed rotates, and in conjunction with this, the other (i.e., left) rear lifter link 72 and the pair of front lifter links 71 rotate similarly. As a result, the cushion frame 4 is displaced in the vertical direction.

[0041] A pair of slide rails 74 and slide levers 75 are devices for displacing the cushion frame 4 in the longitudinal direction. The pair of slide rails 74 are each positioned below a pair of lower arms 41 and extend in the longitudinal direction. Each slide rail 74 has a lower rail 74A that extends in the longitudinal direction and is fixed to the vehicle, and an upper rail 74B that extends in the longitudinal direction and is slidable in the longitudinal direction relative to the lower rail 74A. The slide levers 75 are rod-shaped members that extend in the left-right direction, and both ends are connected to the front ends of the pair of upper rails 74B, respectively.

[0042] [2. Effects] According to the embodiment described in detail above, the following effects can be obtained. (1) Consider a case where a vehicle equipped with a passenger seat is hit, for example, from behind, and the occupant is pressed against the seat back. In this case, the reclining rod 6 of the seat frame 1 receives an external force from the occupant's back in a direction from front to rear, and the reclining rod 6 may deform. As a result, the inner end of the hinge pin 51 of the reclining unit 5 may be displaced rearward. As a result, the locked state (hereafter referred to as the locked state) of the angle of the back frame 2 relative to the cushion frame 4 of the reclining unit 5 may be released.

[0043] Furthermore, the side frame 21 and lower arm 41 receive the external force applied to the reclining rod 6 via the reclining unit 5. As a result, the side frame 21 and lower arm 41 may undergo plastic deformation. Moreover, it is difficult to predict the shape of the side frame 21 and lower arm 41 after plastic deformation (in other words, they may undergo irregular plastic deformation).

[0044] On the other hand, according to the seat frame 1 of the above embodiment, when an external force is applied to the reclining rod 6 in the direction from front to rear, the reclining rod 6 deforms and comes into contact with the first end D1 of the main body portion 31 of the elastic member 3. The external force transmitted from the reclining rod 6 to the elastic member 3 is absorbed by the elastic deformation of the elastic member 3. Therefore, it is possible to suppress further deformation of the reclining rod 6 from the state in which it is in contact with the main body portion 31. Therefore, it is possible to suppress the release of the locked state of the reclining unit 5. In addition, it is possible to suppress plastic deformation of the side frame 21 and the lower arm 41.

[0045] (2) Consider the case in which the lower frame 22 of the seat frame 1 has a shape (hereinafter referred to as the conventional shape) that, in the normal state, extends from behind the reclining rod 6, passes below the reclining rod 6, and curves to the front of the reclining rod 6. With the conventional shape of the lower frame 22, for example, when a vehicle equipped with a passenger seat is rear-ended and the occupant is pressed against the seat back, the front end of the lower frame 22 receives an external force from the occupant in the direction from front to rear. Therefore, deformation of the reclining rod 6 due to the external force from the occupant can be suppressed. However, because the conventional shape of the lower frame 22 is complex and large, the cost of forming the lower frame 22 and the cost of joining the lower frame 22 to the pair of side frames 21 by welding or the like may increase. Also, for the same reason, the weight of the lower frame 22 may increase.

[0046] On the other hand, the elastic member 3 of the seat frame 1 in the above embodiment can apply an elastic force to the reclining rod 6 in a direction from rear to front. Therefore, deformation of the reclining rod 6 can be suppressed without making the lower frame 22 a complex and large shape. As a result, the cost of molding the lower frame 22 and the cost of joining the lower frame 22 to the pair of side frames 21 can be reduced. Also, for the same reason, the lower frame 22 can be made lighter.

[0047] (3) The connecting portion 33 of the elastic member 3 in the above embodiment extends in a direction substantially coinciding with the thickness direction (i.e., the front-to-back direction in the normal state). Therefore, the rigidity of the elastic member 3 against external forces in the front-to-back direction near the connecting portion 33 can be increased. Therefore, when the first end D1 of the main body 31 is subjected to an external force in the direction from front to back, rearward displacement can be suppressed. Therefore, deformation of the reclining rod 6 can be effectively suppressed.

[0048] [3. Other Embodiments] While embodiments of this disclosure have been described above, it goes without saying that this disclosure is not limited to the embodiments described above and can take various forms.

[0049] (1) In the above embodiment, under normal conditions, there is a gap between the main body 31 of the elastic member 3 and the reclining rod 6. When the reclining rod 6 is deformed by an external force from the seated person's back, the reclining rod 6 comes into contact with the main body 31. However, the embodiment is not limited to this, and the reclining rod 6 may be in contact with the main body 31 under normal conditions.

[0050] (2) In the above embodiment, the bent portion 32 includes a connecting portion 33 and a folded portion 34. However, it is not limited to this, and for example, the bent portion 32 does not have to include a folded portion 34. Specifically, for example, the connecting portion 33 extends along the thickness direction from the end of the first end side D1 of the main body portion 31 toward the back side T2, and the end of the back side T2 of the connecting portion 33 may abut against and be joined to the lower frame 22.

[0051] (3) In the above embodiment, the connecting portion 33 extends in a direction substantially coincide with the thickness direction. However, it is not limited to this, and the connecting portion 33 may extend toward the first end side D1 as it approaches the back side T2, or it may extend inclined in the thickness direction toward the second end side D2 as it approaches the back side T2. In addition, the connecting portion 33 may be curved or bent at a position away from the end.

[0052] (4) In the above embodiment, the vehicle seat equipped with the seat frame 1 is used in a passenger car. However, it is not limited to this, and the vehicle seat may be used in automobiles other than passenger cars, or in vehicles other than automobiles such as railway cars, ships and aircraft.

[0053] (5) Multiple functions of one component in the above embodiment may be realized by multiple components, or one function of one component may be realized by multiple components. Also, multiple functions of multiple components may be realized by one component, or one function realized by multiple components may be realized by one component. Furthermore, some of the configurations of the above embodiment may be omitted. Furthermore, at least some of the configurations of the above embodiment may be added to or replaced with the configurations of other above embodiments. [Explanation of symbols]

[0054] 1...Seat frame, 2...Back frame, 21...Side frame, 22...Lower frame, 3...Elastic member, 31...Main body, 32...Bending part, 33...Connecting part, 34...Folding part, 4...Cushion frame, 5...Reclining unit, 6...Reclining rod, D1...First end side, D2...Second end side.

Claims

1. A seat frame used in vehicle seats, It comprises a cushion frame, a back frame, a pair of reclining units, and a reclining rod. The cushion frame constitutes the framework of the seat cushion of the vehicle seat. The aforementioned back frame is a component that constitutes the frame of the seat back of the vehicle seat, A pair of side frames are arranged on both sides in the seat width direction, extending in an extension direction perpendicular to the seat width direction, and the first end in the extension direction is rotatably connected to the rear end of the cushion frame in the seat front-rear direction, about an axis extending in the seat width direction. A lower frame extending in the width direction of the seat and connecting the first ends of the pair of side frames, The sheet comprises an elastic member that is positioned between the pair of side frames in the width direction of the sheet, is elongated in the extension direction, and has elasticity, The pair of reclining units are each positioned on the first end side of the pair of side frames, and are configured to be able to lock and unlock the angle of the pair of side frames relative to the cushion frame. The reclining rod extends in the width direction of the seat and connects the pair of reclining units together. The normal state is when the angle of the pair of side frames relative to the cushion frame is such that the extension direction substantially coincides with the vertical direction of the seat. In the normal state, the reclining rod is located in front of the seat in the front-rear direction relative to the lower frame. The elastic member is In the normal state described above, the main body portion extends in the extension direction so as to pass between the lower frame and the reclining rod in the front-rear direction of the seat, The main body portion includes a bent portion that extends from the first end in the extension direction and is connected to the lower frame, Seat frame.

2. A seat frame according to claim 1, The elastic member is a linear member. Seat frame.

3. A seat frame according to claim 1 or claim 2, The aforementioned bent portion is A folded portion that extends in the aforementioned extension direction and is connected to the lower frame, The system includes a connecting portion that connects the first end portions of the folded portion and the main body portion in the extending direction, Seat frame.

4. A seat frame according to claim 3, The connecting portion extends from the first end of the main body portion in the stretching direction to the first end of the folded portion in the stretching direction, in a direction substantially coinciding with the sheet width direction and the thickness direction perpendicular to the stretching direction. Seat frame.

Images