JP3348543B2 - Vehicle seat back frame structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a seat back frame structure for a vehicle having a top portion including a pair of side portions and a corner portion and having a substantially inverted U shape as a whole.

[0002]

2. Description of the Related Art In general, a seat back of a vehicle seat is configured to have a high strength to constitute a skeletal member and to support a headrest, and is attached to the seat back frame to support an upper body of an occupant. It is generally constituted by a seat back pad and a skin material covering the surface of the seat back pad.

There are various structures of the seat back frame of the seat back described above.
Some seat back frames are constituted by an upper frame provided by being bent into a letter shape, and a pair of side frames of a press-formed product each attached to the lower end of the upper frame by welding. According to this configuration, the seatback frame is composed of three parts, so that the number of parts is increased and the number of manufacturing steps is increased accordingly. A structure devised to solve this problem is disclosed in JP-A-6-70827, and the structure disclosed in this publication will be described below.

As shown in FIG. 16, in the structure disclosed in this publication, a seat back frame 140 is constituted by an upper seat back frame 148 and a lower seat back frame 150. Among them, the upper seat back frame 148 includes a pair of wide side portions 152 disposed on the left and right, and a corner portion 1 extending upward from each upper end of each of the side portions 152.
Top portion 156 formed in a substantially inverted U shape including
And are integrally formed. In addition, the lower seat back frame 150 is welded to the lower rear surface of the pair of side portions 152.

[0005] The upper seat back frame 148 will be described in more detail.
(A) is formed in a substantially U-shaped cross section,
A concave bead 158 is formed at the center in the width direction. At the center of the bead 158, an opening 160 is formed for reducing the weight or the like. Also, the top part 15
6 has a substantially C-shaped cross section as shown in FIG. 17 (B), and both end portions 154A are both bent toward the axial center side and arranged close to each other. Have been. Further, the headrest support portion 157 of the top portion 156 is formed in a substantially rectangular cross section as shown in FIG.
57A are both bent toward the shaft center and are arranged close to each other.

The above-described upper seat back frame 14
In the case of manufacturing No. 8, the following procedure is generally performed. First, FIG.
As shown in FIG. 8A, the base material 162 conforming to the developed shape of the upper seat back frame 148 is punched from the base material by press molding (pressing step). At this time, a bead 158 of the side portion 152 and the like are also manufactured.
Next, as shown in FIG. 18B, predetermined portions of the punched base material 162 (the side portion 152 and the top portion 1).
A portion [a] connected to the portion 56, a portion [b] corresponding to the corner 154 of the top portion 156, and a crushed portion [c] where the headrest support portion 157 is formed are welded (welding step). Next, as shown in FIG. 18C, the pair of side portions 152 are bent in the same direction by bending. Thereafter, as shown in FIG. 18D, the central portion of the top portion 156 is crushed to form a headrest support portion 157.

Therefore, according to the above configuration, since the upper seat back frame 148 is integrally formed, an increase in the number of parts is not caused and an increase in the number of manufacturing steps caused by the increase in the number of parts can be solved. .

[0008]

However, in the case of the structure disclosed in the above publication, the left and right side portions 15 are not provided.
2 (a substantially U-shaped open cross section) and a top portion 15
6, the lower end of the corner 154 (closed cross section of a substantially circular shape)
Since no consideration is given to the manner of connection with the connecting portion, there is a problem that the change in the section coefficient at the connecting portion (the portion viewed in the direction of the arrow A in FIG. 16) is large. For this reason, when a relatively large load is applied to the top portion 156 toward the rear of the vehicle, stress tends to concentrate on the connecting portion, which is disadvantageous in strength.

In view of the above facts, the present invention minimizes the occurrence of stress concentration at the joint between the left and right side portions and the top portion even when a relatively large load applied to the rear of the vehicle is applied to the top portion. It is an object of the present invention to obtain a vehicle seat back frame structure that can be used.

[0010]

According to the first aspect of the present invention, a pair of side portions having a substantially U-shaped open cross section and a corner portion having a substantially circular closed cross section are provided. And a top portion connected to the pair of side portions, the vehicle seat back frame structure having a generally inverted U-shape as a whole, wherein the side portions are formed of a pair of flanges.
It has a flange portion, gradually connecting portion to move to a corner portion of said closed top portion is a sectional from the open side portion is a sectional, extending from the flange portion to the section inwardly
It is characterized in that a gradual-change flange portion is provided to prevent a sudden change in the section modulus due to a gradual change in the extension length when it is extended . According to the second aspect of the present invention, a pair of wide side portions disposed in both widthwise side portions of the seatback and extending in the seatback height direction, and along the width direction of the seatback in the upper end portion of the seatback. And a top portion connected to a pair of side portions via a corner portion. The vehicle seat back frame structure is generally formed in a substantially inverted U-shape. A base portion constituting a general surface of the portion, a pair of side portions bent to the inside of the seat back from both side portions of the base portion, and bent substantially in parallel from an end portion of each side portion to the center side of the base portion. A pair of flanges, and a substantially U-shaped open cross-section including a top portion, the corner portion of the top portion, a substantially C-shaped cross-section of the corner base, the corner base from both ends of the corner base And a pair of corner ends bent toward the center and abutting each other. The closed section is formed in a substantially circular shape, and further, at least the top portion is the closed section from the side portion being the open section. A connecting portion that transitions to a corner portion of the portion is provided with a gradually changing flange portion that extends inward in cross section from the pair of flange portions and that is connected to the pair of corner ends and whose extension length gradually changes. , Is characterized.

According to a third aspect of the present invention, there is provided a pair of wide side portions disposed in both side portions in the width direction of the seat back and extending in the height direction of the seat back, and the width direction of the seat back in the upper end portion of the seat back. And a top portion connected to a pair of side portions via a corner portion, and a vehicle seat back frame structure formed substantially in an inverted U shape as a whole, ,
A base portion forming a general surface of the side portion, a pair of side portions bent from both sides of the base portion to the inside of the seat back, and bent approximately in parallel from an end portion of each side portion to the center side of the base portion. And a pair of first flange portions, each of which has a substantially U-shaped open cross section, and a corner portion of a top portion is formed from a corner base portion having a substantially C-shaped cross section and a corner base portion from both ends of the corner base portion. And a pair of first corner ends bent to the center side of each other and abutted against each other.
A connecting portion that transitions from the side portion that is the open cross section to the corner portion of the top portion that is the closed cross section is bent from the pair of first flange portions to the base portion side and has a bending width of the pair of first and second flange portions. A pair of second flange portions having substantially the same width as one corner end and connected to the pair of first corner ends are provided.

According to a fourth aspect of the present invention, in addition to the third aspect of the present invention, further, each of the corners of the top portion is bent from the pair of first corner ends to the corner base side. A second corner end is provided, and the side portion is bent from the pair of second flange portions to the pair of side portions or the pair of first flange portions, respectively, and has a bent width of the second corner end portion. And a third flange portion connected to the pair of second corner ends is provided.

[0013]

According to the first aspect of the present invention, the side portion has a substantially U-shaped open cross section, and the corner portion of the top portion has a substantially circular closed cross section.
Further, it has a connecting portion that gradually transitions from a side portion having an open cross section to a corner portion of a top portion having a closed cross section. And in this invention, since the gradual change flange part for preventing the sudden change of a section modulus is provided in this connection part, the section coefficient of a connection part does not change suddenly. Therefore, even if a relatively large load acts on the top portion of the seat back frame toward the rear of the vehicle, the stress hardly concentrates on the connecting portion. Further
According to the present invention , the above-mentioned side portion has a pair of flange portions, and the gradually changing flange portion extends inward from the flange portion to the inside of the cross section and the extension length gradually changes. As a result, the pair of flanges and the ends of the pair of corners are continuously connected. Therefore, the load is smoothly transmitted. According to the second aspect of the present invention, the side portion has a predetermined open cross section, and the corner of the top portion has a predetermined closed cross section. Since the transition joint portion is provided with a gradually changing flange portion which is extended inward from the pair of flange portions and is connected to the pair of corner ends and whose extension length gradually changes,
The section modulus of the joint does not change suddenly. Therefore, even if a relatively large load acts on the top portion of the seat back frame toward the rear of the vehicle, the stress hardly concentrates on the connecting portion. In other words, the pair of flange portions and the pair of corner end portions are continuously connected by the gradually changing flange portion whose extension length gradually changes, so that smooth load transmission is performed.

In addition, by adopting the above configuration, the section modulus is increased by the provision of the gradually changing flange portion, which is advantageous in strength.

Further, since the corner ends are bent from both ends of the corner base toward the center of the corner base and are in contact with each other, the bending step and the crushing step in manufacturing the seat back frame require the corner end to be bent. There is no risk that the edge protrudes outward in the cross section. That is, it is possible to prevent cross section collapse at the top portion in the manufacturing process. For this reason, in order to prevent this, it is possible to abolish the welding work before the bending step and the crushing step which were conventionally required.

According to the third aspect of the present invention, the side portion is formed with a predetermined open cross section, the corner of the top portion is formed with a predetermined closed cross section, and at least the side portion to the top portion are formed. The connecting portion transitioning to the corner portion is bent from the pair of first flange portions to the base portion side, and has a bending width substantially equal to the width of the pair of first corner ends, and the pair of first corner ends. Since the pair of second flange portions connected to the portions are provided, the section modulus of the connecting portion does not suddenly change, and there is almost no change itself. For this reason, when a relatively large load acts on the top portion of the seat back frame toward the rear of the vehicle, it is possible to further suppress the occurrence of stress concentration at the connecting portion.

[0017] Moreover, since the present invention is substantially to match the bending width of the second flange portion to the width of the first corner edge, 請
The section modulus is increased as compared with the present invention according to claim 2 . Therefore, the strength is further improved.

In addition, according to the present invention, the pair of second flange portions are bent from the pair of first flange portions to the base portion side, respectively. The edge of the flange does not interfere with the seat back pad. Therefore, it is possible to prevent the seat back pad from being damaged.

According to the present invention described in claim 4 , according to claim 3,
In the present invention described above, a second corner end bent from a pair of first corner ends to a corner base side is provided at a corner portion of the top portion, and a pair of second flange portions is provided at a side portion. And a pair of first flange portions, each of which is bent toward the first flange portion side, the bending width is substantially the same as the width of the second corner end portion, and the pair of second flange portions is bent.
Since the third flange portion connected to the corner end is provided, the section modulus is further increased by the amount provided with the second corner end and the third flange, in addition to the operation of the present invention according to claim 3 . be able to. Therefore, a high-strength seatback frame with a simple configuration can be obtained without increasing the size of the seatback frame and complicating the manufacturing method.

[0020]

[First Embodiment] A first embodiment will be described below with reference to FIGS. In these figures, the arrow FR shown as appropriate
Indicates the front side of the vehicle, the arrow UP indicates the upper side of the vehicle, and the arrow IN indicates the interior side of the vehicle. The first embodiment corresponds to an embodiment of the present invention described in claims 1 and 2 .

FIG. 4 is an external perspective view of the front seat 10 of the automobile. As shown in this figure,
The front seat 10 includes a seat cushion 12 for seating an occupant, and a seat back 14 that is disposed in an upright state from the rear end of the seat cushion 12 and supports the upper body of the occupant.
And a headrest 16 provided at the upper end of the seat back 14 to support the head of the occupant. Further, the seat back 14 is
Frame-shaped seat back frame 18 constituting the skeletal member of
And a seat back pad 20 attached to the seat back frame 18 and capable of being elastically deformed, and a skin material 22 covering the surface of the seat back pad 20.

Next, referring to FIGS. 1 to 3, a seat back frame 18 which is a frame member of the seat back 14 will be described.
Will be described in detail.

As shown in FIG. 1, the seat back frame 18 includes a pair of left and right side portions 24 disposed on both sides in the width direction of the seat back 14 and extending in the height direction of the seat back 14. And a top portion 28 disposed along the width direction of the seat back 14 and connected to the pair of side portions 24 through the corner portions 26 in the upper end portion of the seat back 14. It is formed in a shape.

More specifically, the top portion 28
3A, a corner base 26A having a substantially C-shaped cross section and a pair of bent ends from both ends of the corner base 26A toward the center of the corner base 26A, as shown in FIG. And a corner end 26B. Further, a pair of corner ends 26B
Are in contact with each other, thereby forming a closed cylindrical cross section. The corner end 26B is located inside the seat back frame 18.

The general portion 30 of the left and right side portions 24
In this case, as shown in FIG. 3B, a base portion 30A which is arranged with a surface including the seat front-rear direction and the seat height direction as a plane direction and forms a general surface of a side portion, and the base portion 30A A pair of side portions 30B bent at substantially right angles from the both sides (ie, both ends in the front-rear direction side) to the inside of the seat back, and the base portion 30 from the tip of each side portion 30B.
And a pair of flange portions 30C bent substantially in parallel toward the center of A. Therefore, the general portion 30 of the left and right side portions 24 has a substantially U-shaped open cross section. In addition, a bead 3 which is a substantially isosceles triangular concave portion in a side view is provided at the center of the base portion 30A.
2 are formed.

Further, the upper end of the top portion 28 (ie,
In the headrest support portion 34), as shown in FIG. 3 (C), the headrest support base 34A having an elliptical cross section is provided.
And a pair of headrest support ends 34B bent from both ends of the headrest support base 34A toward the center of the headrest support base 34A. Further, the pair of headrest support end portions 34B are in contact with the pair of corner end portions 26B of the corner portion 26 in the same manner as described above, thereby forming an oval tubular closed cross section. The headrest support end 34B
Are located on the inner side of the seat back frame 18.

Here, in this embodiment, the general portion 30 of the side portion 24 having the above-mentioned substantially U-shaped open cross section is further provided.
A gradual-change flange portion 30D is formed at a connecting portion (a portion viewed in the direction of the arrow D in FIG. 1) that transitions from the top to the corner portion 26 of the top portion 28, which is a cylindrical closed cross section. Hereinafter, the gradually changing flange portion 30D will be described in detail.

FIG. 2 shows the connecting portion in an enlarged state. As shown in the figure, a pair of gradually changing flange portions 30D extending from the pair of flange portions 30C to the inside of the cross section of the side portion 24 are integrally formed at the connecting portion of the side portion 24. This gradually changing flange 3
The upper end of 0D is connected to a pair of corner ends 26B located at the lower end of the top portion 28. Further, the extension length of the gradually changing flange portion 30D gradually increases from the lower end toward the upper end, and in that sense, the extension length and thus the section modulus continuously and gradually change.

The section L where the gradually changing flange portion 30D is formed
Is a predetermined range (range shown in FIG. 2) in the connecting portion. However, it is arbitrarily changed depending on the shape of the seat back frame 18. The pair of corner ends 26B located on the upper end side of the gradually changing flange portion 30D are welded to prevent the cross section from opening. Further, the upper end position of the bead 32 formed on the base portion 30A of the side portion 24 is set slightly below the formation section L of the gradually changing flange portion 30D.

Hereinafter, the operation of the present embodiment will be described with reference to the manufacturing process of the seat back frame 18.

First, as shown in FIG. 5A, a base material 36 conforming to the developed shape of the seat back frame 18 is punched out of a base material such as a steel plate and manufactured (pressing step). At this time, in the process of pressing with the arrow direction in the figure as the pressing direction, the cross-sectional shape of the general portion 30 of the side portion 24 and the corner portion 26 of the top portion 28 and the cross-sectional shape of the connecting portion are formed, and Twenty-four beads 32 are simultaneously formed.

Next, as shown in FIG. 5B, the base material 36 manufactured in the pressing step is bent in the same direction at the corners 26 of the top portion 28 (bending step).

Next, as shown in FIG. 5C, a predetermined range of the upper end of the top portion 28 of the seat back frame 18 manufactured in the bending process is crushed (headrest crushing process). As a result, an oval tubular headrest support portion 34 is formed at the upper end of the top portion 28 as shown in FIG.

Thereafter, as shown in FIG. 5D, a predetermined portion of the seat back frame 18 manufactured in the headrest crushing step is welded (welding step). Specifically, welding is performed at two places, that is, the upper end portion of the connecting portion and the headrest support portion 34 of the top portion 28. Thus, the seat back frame 18 having a substantially inverted U-shape in a front view is manufactured.

According to the seat back frame 18 of the present embodiment manufactured through the above-described manufacturing process, the pair of left and right side portions 24 having an approximately U-shaped open cross section is replaced by a top portion 28 having a tubular closed cross section. Is provided with a gradually changing flange portion 30D whose extension length gradually increases from the lower end toward the upper end side, so that the side portion 24 and the top portion 28 are connected to each other. The section modulus of the connecting portion can be gradually changed. That is,
There is no place where the section modulus changes suddenly at the joint. For this reason, even if a relatively large load is applied to the top portion 28 of the seat back frame 18 toward the rear of the vehicle, it is possible to minimize the occurrence of stress concentration at the joint. In other words, the pair of flange portions 30C and the top portion 28 of the side portion 24 are formed by the gradually changing flange portion 30D whose extension length gradually changes.
Since the pair of corner ends 26B are continuously connected, smooth load transmission can be achieved.

Further, according to the present embodiment, the section modulus of this portion can be increased by the provision of the gradually changing flange portion 30D, so that the strength can be improved.

The above is the basic effect of this embodiment.
According to this embodiment, the following effects can be obtained.

First, the corner portion 26 of the top portion 28
In this case, a pair of corner ends 26B are brought into contact with each other so as to form a closed cross section of a tubular shape.
In No. 4, a pair of headrest support ends 34B abut each other so as to form an oval tubular closed cross section.
8 can be improved. For this reason, the rigidity of the top portion 28 can be improved.

Secondly, by causing the pair of corner ends 26B to abut (interfere with each other) and the pair of headrest support ends 34B to abut (interfere with each other), a load acts on the top portion 28. Time and seat back frame 18
It is possible to prevent the cross section from being broken at the time of manufacturing (bending step or headrest crushing step) and to improve the torsional rigidity. In this regard, conventionally, in order to secure the strength and prevent the cross-section from breaking, the top portion 28 is subjected to a bending step and a headrest crushing step.
Is welded to the corner 26 and the like, but according to the present embodiment, the same or higher strength can be obtained without welding to the corner 26, so that the welding operation can be reduced. it can.

Third, since the second effect can be obtained, the welding operation on the seat back frame 18 is performed simultaneously with another welding operation (for example, the mounting operation of the seat back spring 38). Can be
This can contribute to cost reduction.

Fourth, since the welding process can be performed at once at the end, welding management is also facilitated. Further, since the pair of corner ends 26B and the headrest support end 34B are in contact with each other, that is, in a state where the surfaces are aligned, the welding work is also easy in this respect, and the welding management is further improved. It will be easier. Second Embodiment Hereinafter, a second embodiment will be described with reference to FIGS. The same components as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted. Further, the second embodiment corresponds to an embodiment of the present invention described in claim 3.

As shown in these figures, in this embodiment, instead of the gradually changing flange portion 30D provided at the connecting portion (see the arrow D in FIG. 1), the width is not changed gradually but is made equal. It is characterized in that the second flange portion 30E is used. That is, as shown in FIGS. 7A and 7C, the corner portion 26 of the top portion 28 and the headrest support portion 34 have closed circular and elliptical tubular cross sections. Are the same as in the first embodiment. In the present embodiment, for convenience of explanation, the pair of flange portions 30C of the side portion 24 described above is referred to as the “first flange portion 30”.
C "and a pair of corner ends 26 of the top portion 28
B is referred to as “first corner end 26B”, and the pair of headrest support ends 34B is referred to as “first headrest support end 3”.
4B ".

However, as shown in FIG. 7 (B), the general portion 30 of the side portion 24 has a substantially U-shaped open cross-section, but the pair of first flange portions 30 is formed.
These are further bent from C to the base portion 30A side to provide a pair of second flange portions 30E. These pair of second flange portions 30E are set to have substantially the same width dimension as the first corner end portion 26B of the corner portion 26 and the first headrest support end portion 34B of the headrest support portion 34, It is continuously provided not only at the connecting portion but also at the general portion 30. Therefore, the first headrest support end 30A of the headrest support portion 34 of the top portion 28
Is continuously connected to the first corner end 26B of the corner portion 26 as it is, and the first corner end 26B of the corner portion 26 is continuously extended as it is to the connecting portion of the side portion 24 and the general portion 30. The second flange portion 30
E.

According to the above configuration, the gradually changing flange portion 30D
In place of the second flange portion 30E, the section modulus of the connecting portion does not suddenly change and hardly changes. For this reason, when a relatively large load is applied to the top portion 28 of the seat back frame 18 toward the rear of the vehicle, it is possible to further suppress the occurrence of stress concentration at the connecting portion as compared with the first embodiment described above. it can.

Further, in the present embodiment, the second flange portion 30E is provided instead of the gradually changing flange portion 30D at the connecting portion, and the equal width flange portion 30D is provided over the entire pair of side portions 24. Side part 2 including joints
4 can be increased. Therefore, according to the present embodiment, it is possible to obtain the seat back frame 18 with higher strength.

Further, in this embodiment, since the pair of second flange portions 30E are provided by bending the pair of first flange portions 30C further toward the base portion 30A, they are strong at the time of collision or the like. Even when the load is received by the seat back 14, there is no problem that the edge of the second flange portion 30E protrudes outward in cross section and interferes with the seat back pad. Therefore, it is possible to prevent the seat back pad 20 from being damaged without providing a separate component such as a felt. Since the space where the second flange portion 30E is provided is usually a dead space, there is no restriction on space. Third Embodiment Hereinafter, a third embodiment will be described with reference to FIGS. Note that the same reference numerals are given to the same components as those in the first embodiment and the second embodiment, and description thereof will be omitted. Further, the third embodiment corresponds to an embodiment of the present invention described in claim 4.

As shown in FIGS. 8 and 9, in this embodiment, the distal ends of the pair of second flange portions 30E of the side portion 24 are further bent substantially perpendicularly to the pair of side portions 30B. It is characterized in that three flange portions 30F are provided.

That is, as shown in FIG.
In the first embodiment and the second embodiment described above, the corner portion 26 of the top portion 28 has a substantially tubular closed cross section.
This is the same as the embodiment, except that the tip of the first corner end 26B is further bent at a substantially right angle toward the corner base 26A to provide the second corner end 26C. Similarly, as shown in FIG. 9C, the headrest support portion 34 of the top portion 28 is similar in that it has a substantially oval tubular closed cross section, but the first headrest support end portion The difference is that the distal end of 34B is further bent at a substantially right angle toward the headrest support base 34A to provide a second headrest support end 34C.

On the other hand, as shown in FIG. 9 (B), in the side portion 24, the distal end portions of the pair of second flange portions 30E are further paired over the entirety of the general portion 30 including the connecting portion. The third flange portion 30F is formed by being bent at a substantially right angle to the side portion 30B side of the third flange portion 30B. This third flange portion 30F
Is set to be substantially the same as the width dimension of the second corner end 26C of the corner 26 of the top portion 28 and the second headrest support end 34C of the headrest support 34. Therefore, the second headrest supporting end 34C of the headrest supporting portion 34 of the top portion 28 is connected to the second corner end 26C of the corner 26 as it is, and furthermore, the second corner end 26C of the corner 26 is connected. Is continuously extended to the connecting portion of the side portion 24 and the general portion 30 to form a third flange portion 30F.

The sectional shape of the above structure is manufactured as follows. First, the corner portion 26 of the top portion 28 will be described. As shown in FIG. 10A, a lower mold 52 having a shallow concave portion 50 and a convex portion 54 having a small protrusion amount.
The flat base material 58 is press-formed using the upper mold 56 having Thereby, the second corner end 26C bent in the same direction is formed first at both ends in the width direction of the base material 58,
The primary processed product 60 is manufactured. Next, as shown in FIG. 10B, a relatively shallow concave portion 62 having a substantially semicircular cross section.
And a relatively wide rectangular parallelepiped projection 6
6 obtained by using the upper mold 68 having the
Press molding. As a result, the central portion of the primary processed product 60 is pressed by the protrusion 66 until the pair of second corner ends 26C abut on both side surfaces of the protrusion 66, and the substantially semicircular secondary processed product 70 is manufactured. You. Next, as shown in FIG. 10C, a lower mold 74 having a relatively deep concave portion 72 having a substantially semicircular cross section, a rectangular parallelepiped projection 76 having a relatively narrow width, and both sides of the projection 76 are provided. Using the upper die 80 having the inclined recessed portion 78, the obtained secondary processed product 70 is press-formed. As a result, the pair of second corner ends 26C descend along both side surfaces of the protrusion 76, and a part of the corner base 26A enters the inclined recess 78 to form the first corner end 26B. Thus, a tertiary processed product 82 that is longer than the secondary molded product 70 is manufactured. Then, FIG.
As shown in (D), the obtained tertiary processed product 82 is press-formed using a lower die 86 having a concave portion 84 having a semicircular cross section and an upper die 90 having a concave portion 88 having a semicircular cross section. As a result, the pair of first corner ends 26B come into contact with each other and adhere to each other, and the pair of second corner ends 2B.
6C faces the corner base 26A side, and the corner 26 is obtained.

Next, the general portion 30 of the side portion 24 will be described. Since the general portion 30 is basically the same as the corner portion 26, a brief description will be given. Although not shown in FIG. 11, the same steps as those shown in FIG. 10A are performed in this case. The primary processed product 60 obtained in this step is
As shown in FIG. 1 (A), press molding is performed using a lower mold 94 having a relatively shallow rectangular concave portion 92 and an upper mold 98 having a relatively wide rectangular parallelepiped projection 96.
As a result, the central portion of the primary processed product 60 is brought into contact with the protrusions 9 until the pair of third flange portions 30F abut on both side surfaces of the protrusion 96.
6 to produce a substantially U-shaped secondary processed product 100. Then, as shown in FIG. 11B, a lower mold 104 having a relatively deep rectangular cross-section concave portion 102 and an upper mold 108 having a relatively narrow rectangular parallelepiped projection 106 are obtained. The secondary processed product 100 is press-formed.
As a result, the pair of third flange portions 30 </ b> F
And a pair of second flange portions 30E are formed on the bottom surface side of the upper mold 108 to manufacture the tertiary processed product 110. Thereafter, as shown in FIG. 11C, a lower mold 114 having a concave portion 112 having a rectangular cross section is provided.
The obtained tertiary processed product 110 is press-formed by using an upper die 118 having a projection 116 having a narrow width. As a result, the pair of third flange portions 30F moves toward the pair of side portions 30B, and the pair of second flange portions 30E are located on both side surfaces of the protrusion 116, so that the general portion 30 of the side portion 24 is moved. can get.

According to the above configuration, the same operation and effect as in the second embodiment can be obtained. Further, in this embodiment,
Since the second corner end 26C and the second headrest support end 34C are newly provided on the top portion 28, and the third flange portion 30F is newly provided on the side portion 24,
The section modulus can be increased accordingly. Therefore, according to the present embodiment, it is possible to obtain the seat back frame 18 with higher strength without increasing the size of the seat back frame 18 and complicating the manufacturing method. Fourth Embodiment Hereinafter, a fourth embodiment will be described with reference to FIGS. In addition, the same reference numerals are given to the same components as those in the first to third embodiments, and the description thereof will be omitted. Further, the fourth embodiment corresponds to an embodiment of the present invention described in claim 4.

As shown in FIGS. 12 and 13, in this embodiment, the third flange portion 30G (the hemming portion) is mainly formed by further folding back the tip portions of the pair of second flange portions 30E of the side portion 24 and bringing them into close contact. ) Is characteristic.

In other words, as shown in FIG. 13 (A), the corners 26 of the top portion 28 have a substantially cylindrical closed cross section, and the first to third embodiments have been described.
The third embodiment is the same as the third embodiment, except that the second corner end 26D, which is a hemming portion, is provided by further folding and adhering the tip of the first corner end 26B. . Similarly, as shown in FIG. 13 (C), the headrest support portion 34 of the top portion 28 is similar in that it has a substantially elliptical tubular closed cross section. The tip of 34B is further folded back and brought into close contact with the second part, which is a hemming part.
The difference is that a headrest support end 34D is provided.

On the other hand, as shown in FIG. 13B, in the side portion 24, the tip portions of the pair of second flange portions 30E are further folded over the whole of the general portion 30 including the connecting portion. The third flange portion 30G, which is a hemming portion, is formed by being closely attached. The width dimension of the third flange portion 30G is set substantially equal to the width dimension of the second corner end portion 26D of the corner portion 26 of the top portion 28 and the second headrest support end portion 34D of the headrest support portion 34. I have. Therefore, the top portion 28
The second headrest support end portion 34D of the headrest support portion 34 is continuously connected to the second corner end portion 26D of the corner portion 26 as it is, and the second corner end portion 26D of the corner portion 26 is continuously connected as it is. The third flange portion 30G is extended to the connecting portion of the side portion 24 and the general portion 30.

The manufacturing process of the sectional shape of the above configuration is shown in FIGS. 14 and 15, and is basically the same as that of the third embodiment described above (see FIGS. 10 and 11). Therefore, the description is omitted. The difference from the third embodiment is that
The point is that a hemming part necessary for producing a primary processed product is provided.

With the above configuration, the same effects as in the third embodiment can be obtained. Further, according to the present embodiment,
There is an advantage that the formability is good even when the cross section of the top portion 28 has a small diameter. That is, in the third embodiment, FIG.
In the step shown in (C), the second corner end 26
Since C is restricted when it enters the inclined recess 78,
If the cross section of the top portion 28 has a small diameter, molding becomes difficult. However, according to the present embodiment, such a problem does not occur because hemming is performed in advance.

In the first embodiment, the gradually changing flange portion 30D is provided only at the connecting portion. However, the present invention is not limited to this, and the gradually changing flange portion 30D is provided from the connecting portion to the lower end of the general portion 30. Is also good. Conversely, in the second to fourth embodiments, the entirety of the general portion 30 including the connecting portion includes the second flange portion 30E,
Although the third flange portion 30F is provided, it is sufficient that these are provided at least in the connecting portion.

[0059]

As described above, the vehicle seat back frame structure according to the first aspect of the present invention has a connecting portion that gradually transitions from a side portion having an open cross section to a corner portion of a top portion having a closed cross section. In addition, since the connecting portion is provided with a gradually changing flange portion for preventing a sudden change in the section modulus, even when a relatively large load to the rear of the vehicle is applied to the top portion, the left and right side portions and the top portion are provided. This has an excellent effect that it is possible to minimize the occurrence of stress concentration at the connecting portion with the connecting member. The vehicle seat according to the present invention is also provided.
According to-back frame structure, the side portion has a pair of flanges, the gradually-varying flange portion is formed by extending the length with extended from the flange portion to the cross-section inward to gradually change Therefore, an excellent effect that the pair of flange portions and the end portions of the pair of corner portions are continuously connected to each other to smoothly transmit the load is obtained. further,
In the vehicle seat back frame structure according to the second aspect of the present invention, at least a connecting portion that transitions from a side portion that is an open cross section to a corner portion of a top portion that is a closed cross section has a cross section inward from a pair of flange portions. And a gradually changing flange that is connected to a pair of corner ends and has a gradually changing extension length. Has an excellent effect of minimizing the occurrence of stress concentration at the joint between the side portion and the top portion.

According to a third aspect of the present invention, there is provided a vehicle seat back frame structure according to the present invention, wherein at least a connecting portion transitioning from a side portion having an open cross section to a corner portion of a top portion having a closed cross section has a pair of first and second connecting portions. Each of the first and second corners is bent from the one flange portion toward the base portion, and has a bending width substantially equal to the width of the pair of first corner ends.
Since a pair of second flanges connected to the corner ends is provided, stress concentrates on the joint between the left and right side parts and the top part even when a relatively large load is applied to the top part at the rear of the vehicle. Can be suppressed as compared with the present invention described in claim 3.

According to a fourth aspect of the present invention, there is provided the vehicle seat back frame structure according to the third aspect of the present invention, further comprising: In addition to providing the second corner end bent to the side, the side portion,
Each of the pair of second flange portions is bent toward the pair of side portions or the pair of first flange portions, respectively, and has a bending width substantially equal to the width of the second corner end portion. is provided with the third flange portion connected, 請
In addition to the effects of the present invention described in claim 3, there is provided an excellent effect that a high-strength seatback frame can be obtained with a simple configuration without increasing the size of the seatback frame and complicating the manufacturing method. Have.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a seat back frame according to a first embodiment.

FIG. 2 is an enlarged perspective view showing a connecting portion between a side portion and a top portion in the seat back frame shown in FIG.

FIG. 3 is a cross-sectional view showing a cross-sectional structure of each part of the seat back frame shown in FIG. 1, where (A) is 3 (A) of FIG. 1;
FIG. 3B is a sectional view taken along line -3 (A), and FIG.
3 (B) is a sectional view taken along line 3 (B), and FIG. 3 (C) is 3 (C) -3 in FIG.
(C) It is a sectional view taken on a line.

FIG. 4 is an overall perspective view showing a front seat provided with the seat back frame shown in FIG. 1;

FIG. 5 is a process diagram for explaining a manufacturing process of the seat back frame shown in FIG.

FIG. 6 is a perspective view of a connecting portion corresponding to FIG. 2 and showing a structure of a seat back frame according to a second embodiment.

7 is a cross-sectional view corresponding to FIG. 3, showing a cross-sectional structure of each part of the seat back frame shown in FIG. 6;

FIG. 8 is a perspective view of a connecting portion corresponding to FIG. 6 and showing a structure of a seat back frame according to a third embodiment.

9 is a sectional view corresponding to FIG. 7 and showing a sectional structure of each part of the seat back frame shown in FIG. 8;

FIG. 10 is a process chart for explaining a procedure for manufacturing a corner portion of a top portion according to the third embodiment.

FIG. 11 is a process chart for explaining a procedure for manufacturing a general portion of a side portion according to the third embodiment.

FIG. 12 is a perspective view of a connecting portion corresponding to FIG. 8 and showing a structure of a seat back frame according to a fourth embodiment.

13 is a sectional view corresponding to FIG. 9 and showing a sectional structure of each part of the seat back frame shown in FIG. 12;

FIG. 14 is a process chart for explaining a procedure for manufacturing a corner portion of a top portion in the fourth embodiment.

FIG. 15 is a process chart for explaining a procedure for manufacturing a general portion of the side portion according to the fourth embodiment.

FIG. 16 is a perspective view showing a conventional seat back frame structure.

17 is a sectional view showing a sectional structure of each part of the upper seat back frame shown in FIG. 16;

FIG. 18 is a process chart for describing a manufacturing process of the upper seat back frame shown in FIG.

[Explanation of symbols]

14 seat back 18 seat back frame 24 side part 26 corner 26A corner base 26B (first) corner end 26C second corner end 28 top part 30A base 30B side 30C (first) flange 30D gradually changing flange Section [Claims 1 and 2 ] 30E Second flange section [ Claim 3 ] 30F Third flange section [ Claim 4 ] 30G Third flange section [ Claim 4 ]

Claims (4)

(57) [Claims] 1. A pair of side portions each having a substantially U-shaped open cross section and a pair of side portions connected through a corner portion having a substantially circular closed cross section. And a top part, comprising a vehicle seat back frame structure formed substantially in an inverted U-shape as a whole, wherein the side part has a pair of flange parts, and is formed from the side part which is the open cross section. The connecting portion that gradually transitions to the corner of the top portion, which is the closed cross section,
Extends inward from the flange section and extends
There is provided a gradual change flange portion for preventing the sudden change of section modulus by gradually changing, the vehicle seat back frame structure, characterized in that. 2. A pair of wide side portions disposed in both widthwise side portions of the seat back and extending in the height direction of the seat back, and corners disposed in the upper end portion of the seat back along the width direction of the seat back. And a top portion connected to the pair of side portions via the portion, and a vehicle seat back frame structure formed in a substantially inverted U shape as a whole, wherein the side portion is a general surface of the side portion. A pair of side portions bent from both sides of the base portion to the inside of the seat back, and a pair of flange portions bent substantially in parallel from the end of each side portion toward the center of the base portion. And a substantially U-shaped open cross-section including: a top portion having a corner portion having a substantially C-shaped cross section, and a corner portion extending from both ends of the corner base portion to the center of the corner base portion. And a pair of corner ends bent and abutted with each other, and a substantially circular closed cross section including: a corner portion from at least a side portion that is the open cross section to a top portion that is the closed cross section. A gradually changing flange portion extending from the pair of flange portions to the inside of the cross section and being connected to the pair of corner ends and having a gradually changing extension length is provided on the connecting portion. Vehicle seat back frame structure. 3. A pair of wide side portions arranged in both widthwise side portions of the seatback and extending in the height direction of the seatback, and corners arranged in the upper end portion of the seatback along the width direction of the seatback. And a top portion connected to the pair of side portions via the portion, and a vehicle seat back frame structure formed in a substantially inverted U shape as a whole, wherein the side portion is a general surface of the side portion. , A pair of side portions bent from both sides of the base portion to the inside of the seat back, and a pair of first portions bent substantially in parallel from ends of the respective side portions to the center side of the base portion. A flange section and a substantially U-shaped open cross section including a top section, and a corner section of the top section is formed from a corner base section having a substantially C-shaped cross section and both ends of the corner base section to the center side of the corner base section. And a pair of first corner ends bent and abutted to each other, each of which has a substantially circular closed cross section, and further includes at least a top portion which is the closed cross section from a side portion which is the open cross section. The connecting portion that transitions to the corner portion is bent from the pair of first flange portions to the base portion side, and has a bending width substantially equal to the width of the pair of first corner end portions. First
A vehicle seat back frame structure, comprising: a pair of second flange portions connected to corner ends. Further, a second corner end bent from the pair of first corner ends to the corner base side is provided at a corner of the top part, and the pair of the pair of corners is provided at the side part. The second flange portion is bent toward the pair of side portions or the pair of first flange portions, respectively, and has a bending width substantially equal to the width of the second corner end portion, and the pair of second corner end portions. The vehicle seat back frame structure according to claim 3 , further comprising a third flange portion connected to the vehicle.