JP6624058B2 - Seat frame - Google Patents

Description

  The present invention relates to a seat frame, and more particularly to a seat frame in which weight reduction and rigidity are taken into consideration.

The members provided in the vehicle need to secure rigidity while reducing the weight for the purpose of improving fuel efficiency.
In view of this, it is known that the seat frame forming the skeleton of the vehicle seat is formed of resin instead of metal (for example, Patent Document 1).
In particular, FIG. 13 of Patent Literature 1 describes a side frame formed into an I-shaped cross section that constitutes a seat frame.
Some seat back frames, which are frames of a backrest portion of a vehicle seat, have a configuration in which yoke members are welded to left and right side frames. The load applied to the side frame (side beam) may be reduced by a load applied to the yoke member from a seated person. In Patent Document 2, in order to avoid this reduction in load resistance, a spacer member as a yoke member connected to a thin metal plate is provided between left and right side frames constituting a seat back frame. Discloses a technique for fixing a side frame.

JP 2013-227007 A JP-A-59-57034

However, the vehicle seat disclosed in Patent Document 1 is not sufficient in terms of weight reduction for improving fuel efficiency, and it is difficult to secure rigidity when the weight is reduced.
Further, according to the invention described in Patent Document 2, by attaching the spacer member to the side frame via the thin metal plate, it is possible to prevent the torsion load from being applied to the side frame due to the load from the occupant's back. However, there was no change in that the load resistance of the side frame was reduced by the application of the bending load.
Further, simply increasing the rigidity of the spacer member may hinder weight reduction.
The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a seat frame that is reduced in weight while securing the rigidity of the seat frame.
Another object of the present invention is to provide a lightweight seat frame which can efficiently suppress twisting and bending.

According to the seat frame of the present invention, the object is to provide a seat frame which includes left and right side frames each having an I-shaped cross section extending in a longitudinal direction and forming a skeleton of a seat. Direction, and both ends in the short direction orthogonal to the seat width direction, and an intermediate portion between the both ends, the seat frame is a seat back frame, and the side frame is Extending in the up-down direction as the longitudinal direction, the short direction is the front-rear direction, the both end portions are composed of a front side portion and a rear side portion, and the front side portion or the rear side of the upper part in the side frame. The dimension in the front-rear direction of the part is solved by being smaller than the dimension in the front-rear direction of the lower front part or the rear part of the side frame .

Since the cross-sectional shape of the side frame is I-shaped as in the above configuration, the secondary moment of area and the secondary polar moment of the side frame can be increased, and the bending rigidity and the torsional rigidity can be increased. . Furthermore, the rigidity can be balanced by the symmetry of the cross-sectional shape, and the through-hole is formed in the middle part of the side frame to reduce the weight and secure the rigidity by bracing. be able to. The I-shaped cross section according to the present invention means that both end portions have a cross-sectional shape larger in the sheet width direction than the intermediate portion.
Further, according to the above configuration, the bending rigidity and the torsional rigidity of the side frame of the seat back frame can be increased, and the rigidity balance can be enhanced by the symmetry of the cross-sectional shape.
In addition, according to the above configuration, the front-rear portion or the rear side portion at the lower portion where a load is applied close to the waist of the seated person, and the front-rear portion or the rear side portion at the upper portion are reduced in the front-rear direction. In addition, it is possible to efficiently secure rigidity while considering weight reduction.

Further, the length of the both ends in the sheet width direction is greater than the length of the intermediate portion in the sheet width direction, and the intermediate portion has a lightening hole perforated in the sheet width direction; Preferably, braces are formed across the holes.
In the side frame, it is preferable that dimensions of the upper part and the lower part in the front-rear direction are substantially equal.
Further, it is preferable that a dimension in the sheet width direction at any one of the both ends is larger than a dimension in the short direction at the end.
According to the above configuration, the bending rigidity and the torsional rigidity of the side frame in the seat width direction are increased because the dimension in the sheet width direction at any one of the two end portions is larger than the dimension in the lateral direction at the end portion. , Can be efficiently secured for a predetermined volume.

In addition, it is preferable that a dimension in the short direction at any one of the two end portions is larger than a dimension in the sheet width direction at the intermediate portion.
According to the above configuration, the bending rigidity and the torsional rigidity of the side frame can be ensured while suppressing the dimension in the seat width direction at the intermediate portion of the side frame.

Further, a cross section of the both ends of the side frame may be circular or elliptical.
According to the above configuration, since the cross section of both ends is circular or elliptical and there is no edge, damage to the urethane pad touching both ends can be suppressed.

The length of the side frame in the front-rear direction is shorter in the upper part than in the lower part, and the front-rear part or the rear part in the upper part of the side frame has a front-rear width in the lower part of the side frame. It is preferable that the width is larger than the width of the front portion or the rear portion in the front-rear direction.
According to the above configuration, it is necessary to reduce the length in the front-rear direction of the upper portion of the side frame, which is not an effective portion for supporting the occupant, while securing the rigidity of the front side or the rear side of the upper portion. Therefore, by increasing the width in the front-rear direction, the rigidity of the seat back frame can be ensured and the weight can be efficiently reduced.

Further, it is preferable that the side frame is hardened only in the upper portion having a shorter length in the front-rear direction.
According to the above configuration, the strength can be improved by the quenching process while suppressing the length in the front-rear direction at the upper portion of the side frame.

It is preferable that a plurality of the braces are formed, and at least two of the braces extend away from each other toward the rear of the seat.
According to the above configuration, the supporting force against the load applied to the side frame can be broadly increased, and the rigidity can be efficiently secured.

  Further, the seat frame is a seat back frame that forms a skeleton of a backrest portion, and includes a connection frame that includes a front plate and a rear plate and connects the left and right side frames, and the front plate and the rear side. At least one of the plates is formed with another lightening hole penetrating in the front-rear direction, and a bridging portion extending beyond the other lightening hole, and the front plate and the rear plate are formed. Is solved by being joined at the lower edge of the connection frame.

  As in the above configuration, at least one of the front side plate and the rear side plate is formed with another lightening hole penetrating in the front-rear direction, and an erection portion erected beyond the other lightening hole is formed. As a result, the front plate and the rear plate are joined at the lower edge of the connection frame, so that they can be added to the connection frame from the back of the seated person. A seat frame having high rigidity against a load can be provided.

Further, it is preferable that the front plate and the rear plate are joined in the lower edge of the connection frame near an end of the bridge portion.
According to the above configuration, since the front plate and the rear plate are joined in the vicinity of the end of the erection portion, the rigidity of the connection portion between the front plate and the rear plate where stress tends to concentrate is increased. Can be secured by

Further, it is preferable that the bridging portion extends to a corner of the connection frame.
According to the above configuration, since the bridge portion extends at the corner portion of the connection frame, a reaction force is generated from the corner portion when an external force is applied to the bridge portion, thereby suppressing bending of the bridge portion. Can be.

Further, it is preferable that the erection portion extends toward a connection portion of the connection frame with the left and right side frames.
According to the above configuration, since the connection frame extends toward the connection portion between the left and right side frames in the connection frame, the rigidity of the connection portion between the connection frame and the side frame where stress is easily concentrated can be ensured by the erection portion. Can be.

Further, one side edge portion of the front plate or the rear plate extends toward the other so as to bend and is joined to the other, and the left and right side frames are connected to the connection frame. It is preferable that the portion to be formed has a closed cross-sectional shape by being surrounded by the front plate, the rear plate, and the side edge portion.
According to the above configuration, since the connection frame and the left and right side frames have a closed cross-sectional shape at a portion where they are connected, the rigidity of the portion can be increased.

Further, a guide holder for supporting a part of a headrest frame is attached to the connection frame, and the guide holder is disposed between the front plate and the rear plate, and It is preferable that a part of the portion is disposed so as to overlap the guide holder in the front-rear direction.
According to the above configuration, the connection frame is provided with a guide holder for supporting a part of the headrest frame between the front plate and the rear plate. By being formed to overlap, the rigidity of the guide holder that supports a part of the headrest frame can be efficiently secured by the erection portion.

According to the present invention, the secondary moment of area and the secondary moment of area of the side frame can be increased, and the bending rigidity and the torsional rigidity can be increased. Furthermore, the rigidity can be balanced by the symmetry of the cross-sectional shape, and the through-hole is formed in the middle part of the side frame to reduce the weight and secure the rigidity by bracing. be able to.
Further, according to the present invention, since the dimension in the sheet width direction at any one of the two end portions is larger than the dimension in the lateral direction at the end portion, the bending rigidity and the torsion of the side frame in the sheet width direction are increased. Rigidity can be efficiently ensured for a given volume.
Further, according to the present invention, it is possible to secure the bending rigidity and the torsional rigidity of the side frame while suppressing the dimension in the seat width direction at the intermediate portion of the side frame.
Further, since the cross section of both ends is circular or elliptical and has no edge, damage to the urethane pad touching both ends can be suppressed.
In addition, the bending rigidity and the torsional rigidity of the side frames of the seat back frame can be increased, and the rigidity balance can be enhanced by the symmetry of the cross-sectional shape.
In addition, the front and rear sides of the upper part are smaller than the front and rear parts of the lower part where a load is applied near the waist of the occupant. In addition, the rigidity can be efficiently secured while maintaining the rigidity.
In addition, while reducing the length in the front-rear direction at the upper part of the side frame, which is not an effective part for supporting the occupant, it is necessary to ensure the rigidity of the front part or the rear part of the upper part, By increasing the width in the direction, the rigidity of the seat back frame can be ensured and the weight can be reduced efficiently.
Further, the strength can be improved by quenching while suppressing the length in the front-rear direction at the upper portion of the side frame.
Further, the supporting force against the load applied to the side frame can be broadly increased, and the rigidity can be efficiently secured.
Further, according to the present invention, the weight can be reduced, and the torsion and the bending can be suppressed efficiently. Further, since the front plate and the rear plate are joined at the lower edge of the connection frame, the connection frame can be moved from the back. A seat frame having high rigidity against a load applied to the lower edge side can be provided.
Furthermore, according to the present invention, the rigidity of the connecting portion between the front plate and the rear plate where stress tends to concentrate can be ensured by the bridge portion.
Further, according to the present invention, when an external force is applied to the erection portion, a reaction force is generated from the corner portion, so that bending of the erection portion can be suppressed.
Further, according to the present invention, the rigidity of the connection portion between the connection frame and the side frame where stress is likely to concentrate can be secured by the erection portion.
Further, according to the present invention, it is possible to increase the rigidity of a portion where the connection frame and the left and right side frames are connected.
Further, according to the present invention, the rigidity of the guide holder that supports a part of the headrest frame can be efficiently secured by the erection portion.

It is a perspective view showing the seat back frame concerning a 1st embodiment. FIG. 2 is a cross-sectional view of the side frame, showing a cross section taken along line IIA-IIA of FIG. 1. FIG. 2 is a cross-sectional view of the side frame, showing a cross section taken along line IIB-IIB of FIG. 1. It is a perspective view showing the seat back frame concerning a 2nd embodiment. FIG. 4 is a cross-sectional view of a side frame according to a second embodiment, and is a diagram showing a cross section taken along line IVA-IVA of FIG. 3. FIG. 4 is a cross-sectional view of a side frame according to a second embodiment, and is a diagram illustrating a cross section taken along line IVB-IVB in FIG. 3. It is a figure which shows the example in which the front-back width of the back side part was formed larger than the front-back part front-back width in the side frame which concerns on a modification. It is a figure which shows the example which performed the hardening process on the side frame which concerns on a modification, and shows the example which performed the hardening process on the whole rear side part and the whole front side part. It is a figure which shows the example which performed the quenching process to the side frame which concerns on a modification, and shows the example which performed the quenching process to the whole rear side and the front side part of the back side part. It is a figure which shows the example which performed the hardening process to the side frame which concerns on a modification, and shows the example which performed the hardening process on the left-right side of the rear part, and the left-right side of the front part. It is a figure which shows the example which comprises the side frame which concerns on the modification which two frame pieces of C-shaped cross section were welded back to back. It is sectional drawing of the side frame which concerns on a modification. It is sectional drawing of the side frame which has the hollow part which concerns on a modification. It is sectional drawing of the side frame in which the rear side part was formed larger than the front side part. FIG. 13 is a cross-sectional view of a side frame according to a modification in which two frame pieces are welded back to back. FIG. 11 is an overall perspective view showing a seat back frame according to a third embodiment. It is a rear view of a seat back frame. It is a perspective view which shows the junction part of a back plate and a front plate, and the junction part of an upper frame and a side frame. It is a schematic diagram which shows an example of the joining part of a back side plate and a front side plate. It is a schematic diagram which shows an example of the joining part of a back side plate and a front side plate. It is a schematic diagram which shows an example of the joining part of a back side plate and a front side plate.

  A seat back frame 1, 1a according to an embodiment of a seat frame of the present invention will be described with reference to the drawings.

<< First Embodiment >>
First, the overall configuration of the seat back frame 1 and the overall schematic configuration of the side frame 2 will be described with reference to FIGS. Here, FIG. 1 is a perspective view showing a seat back frame 1 according to the first embodiment, FIG. 2 is a sectional view of a side frame 2, and FIG. 2A is a view showing a IIA-IIA section of FIG. FIG. 2B is a view showing a cross section taken along line IIB-IIB of FIG.

  The seat back frame 1 corresponds to a seat frame according to the present invention, and is formed on a left and right side frame 2 which is disposed on the left and right and extends vertically below the left and right side frames 2 and extends in the seat width direction. And a top frame 3 as a connection frame according to the present invention, which connects the upper portions of the left and right side frames 2 to support the back of a seated person. Hereinafter, the sheet width direction is also referred to as the left-right direction.

  The side frame 2 includes a rear side portion 21 at a rear edge, a front side portion 23 at a front edge, and an intermediate portion 22 connecting the rear side portion 21 and the front side portion 23, each of which extends vertically. The horizontal section has an I-shape.

The rear portion 21 and the front portion 23 are formed to have substantially the same length in the sheet width direction.
The intermediate portion 22 extends substantially vertically at substantially the center in each of the sheet width directions. In particular, in each of the intermediate portions 22 of the left and right side frames 2, a lightening hole 22d is formed in the middle portion in the vertical direction so as to penetrate in the sheet width direction. Lightening is achieved by the lightening holes 22d. Note that the up-down direction corresponds to the longitudinal direction according to the present invention.

Brace holes 22e and 22f are formed in the lightening hole 22d so as to cross in the front-rear direction corresponding to the short direction according to the present invention. By forming the braces 22e and 22f, it is possible to compensate for a decrease in rigidity due to the lightening hole 22d.
In particular, since the lightening hole 22d and the braces 22e and 22f are formed in the side frame 2 having an I-shaped horizontal cross section, the rigidity can be ensured in a well-balanced manner while reducing the weight. It becomes possible.
Furthermore, the braces 22e and 22f extend so as to be apart from each other so as to widen from the front to the rear. By being formed in this way, the supporting force against the load applied to the side frame 2 from the front side can be broadly increased, and the rigidity can be efficiently secured. The number of the braces 22e and 22f may be one or more, and is arbitrary.

  At least one intermediate portion 22 of the side frame 2 is formed with a mounting hole 22g for fixing an airbag, a reclining unit, an actuator, an occupant detection unit, and the like (not shown). When the attachment hole 22g is formed at a position avoiding the extension of the braces 22e and 22f, it is preferable because the rigidity improvement by the braces 22e and 22f is not hindered.

As shown in FIG. 1, the length of the upper portion 2a in the front-rear direction of the side frame 2 is formed shorter than the length of the lower portion 2b in the front-rear direction. With such a configuration, a space near the chest and the arm of the seated person is secured, and the degree of freedom is prevented from being limited.
As shown in FIG. 2A for the horizontal cross section of the upper part 2a and FIG. 2B for the horizontal cross section of the lower part 2b, the front-rear width da of the rear part 21a and the front part 23a of the upper part 2a is the rear part 21b and the front part 23b of the lower part 2b. Is larger than the front-back width db.
As described above, since the front and rear widths da of the rear side portion 21a and the front side portion 23a are formed large, even if the length of the upper portion 2a of the side frame 2 in the front and rear direction is formed short, the section modulus is increased. And the rigidity can be secured.

  In addition, a fillet 24 is formed at a connection portion between the rear side portion 21a and the front side portion 23a of the upper portion 2a and the intermediate portion 22a, and at a connection portion between the rear side portion 21b and the front side portion 23b and the intermediate portion 22b of the lower portion 2b. ing. The fillet 24 is a portion generated when the side frame 2 is forged, and can reinforce a corner where stress concentration occurs. When the probability of deformation due to stress concentration is low, the fillet 24 is not necessarily required.

<< Second Embodiment >>
Next, a seat back frame 1a according to a second embodiment will be described with reference to FIGS. Here, FIG. 3 is a perspective view showing a seat back frame 1a according to the second embodiment, FIG. 4 is a sectional view of a side frame according to the second embodiment, and FIG. 4B is a diagram showing a cross section taken along IVA-IVA, and FIG. 4B is a diagram showing a cross section taken along IVB-IVB in FIG.
The seat back frame 1a according to the second embodiment is different from the seat back frame 1 according to the first embodiment described with reference to FIG. 1, and as shown in FIG. Is formed to be substantially equal to the length of the lower part 7b in the front-rear direction.

The side frame 7 includes a rear side portion 71 at a rear edge, a front side portion 73 at a front edge, and an intermediate portion 72 connecting the rear side portion 71 and the front side portion 73, each of which extends vertically. The horizontal section has an I-shape.
As shown in FIG. 4A for the horizontal cross section of the upper part 7a and FIG. 4B for the horizontal cross section of the lower part 7b, the front and rear widths dd of the rear part 71b and the front part 73b of the lower part 7b are the rear part 71a and the front part 73a of the upper part 7a. Is larger than the front-rear width dc.
With such a configuration, the section modulus of the lower part 7b is larger than that of the upper part 7a in the side frame 7, and the rigidity is increased, so that the waist of the occupant close to the lower part 7b is favorably supported. It becomes possible.
As in the first embodiment, the connection between the rear part 71a and the front part 73a of the upper part 7a of the side frame 7 and the middle part 72a, and the rear part 71b and the front part 73b of the lower part 7b and the middle part A fillet 74 is also formed at the connection portion with 72b.

(First Modification)
Next, the rear side portion 71c and the front side portion 73c in the lower portion 7c of the side frame 7 according to the first modification will be described with reference to FIG. Here, FIG. 5 is a diagram illustrating an example in which the front-rear width dd of the rear side portion 71c is larger than the front-rear width de of the front side portion 73c in the side frame 7 according to the modification.
The front-rear width dd of the rear portion 71c of the side frame 7 is formed larger than the front-rear width de of the front portion 73c. Such a configuration is preferable from the viewpoint of securing rigidity while reducing the weight. This is because the rear side portion 71c is connected to the lower frame 4 and generates a bending moment when an external force is applied, and thus requires higher rigidity than the front side portion 73c.

The front and rear widths dd and de of at least one of the upper part 7a and the lower part 7b of the side frame 7 are formed larger than the lateral width f of the intermediate part 72c. By being formed in this manner, the size of the side frame 7 in the seat width direction can be suppressed to be suitable for mounting an airbag or the like, and the rigidity can be improved by increasing the section modulus.
In this way, the front-rear width dd of the rear side portion 71c is made larger than the front-rear width de of the front side portion 73c, and the front-rear width dd, de of the rear side portion 71c or the front side portion 73c is set to the width f of the intermediate portion 72c. Forming larger than the dimensions is not limited to the side frame 7 according to the second embodiment, but may be applied to the side frame 2 according to the first embodiment. Further, the present invention may be applied to any of the upper portions 2a and 7a and the lower portions 2b and 7b. The same applies to the modifications described below.

(Second Modification)
Next, side frames 70, 70a, 70b according to a second modification will be described with reference to FIG. Here, FIG. 6 is a diagram showing an example in which quenching processing is performed on the side frames 70, 70a, 70b according to the second modification, and FIG. 6A shows the entire rear side portion 71d and the entire front side portion 73d. FIG. 6B is a diagram illustrating an example in which a quenching process is performed, FIG. 6B is a diagram illustrating an example in which a quenching process is performed on the entire rear side and the front side portion 73d of the rear side portion 71e, and FIG. It is a figure showing the example which performed hardening processing on the right and left sides of front side part 73e.

As shown in FIG. 6A, the side frame 70 has a hardened q applied to the entire rear side 71d and the entire front side 73d.
As shown in FIG. 6B, the side frame 70a is hardened q on the entire rear side and the front side 73d of the rear side 71e.
Further, as shown in FIG. 6C, the side frame 70b is hardened q on the left and right sides of the rear side portion 71f and the left and right sides of the front side portion 73e.

By performing quenching q like the side frames 70, 70a, 70b, it is possible to improve strength while suppressing weight increase. Note that the partial quenching as shown in FIGS. 6B and 6C is performed by arranging an induction coil (not shown) only in a portion where quenching q is to be performed, or by moving a work in the induction coil to perform quenching q. This is done by shortening the time.
In particular, the rear side 71e shown in FIG. 6B has a shorter quenching time than the rear side 71d shown in FIG. 6A, and only a part of the rear side is quenched.
Further, the quenching q may be applied to the other side frame 2. Particularly, if the quenching q is applied to the upper portion 2 a of the side frame 2 having a short length in the front-rear direction and low rigidity, the strength is improved and the rigidity is increased. It is suitable.

(Third Modification)
Next, a side frame 70c according to a third modification will be described with reference to FIG.
The side frame 70c is a frame that has a U-shaped cross section and that is formed by joining two frame pieces 70d and 70e made of sheet metal back to back and extending vertically. In each of the frame pieces 70d and 70e constituting the side frame 70c, the rear side plate 75g and the rear side plate 75h and the front side plate 77g and the front side plate 77h are respectively arranged on the same plane. The frame pieces 70d and 70e are welded by the spot welding portion 78 in a state where the intermediate plate 76g and the intermediate plate 76h face each other.
In other words, by being welded in this way, the rear plate 75g and the rear plate 75h constitute the rear portion 75, the intermediate plate 76g and the intermediate plate 76h constitute the intermediate portion 76, and the front plate 77g and the front plate The front side 77 is constituted by the side plate 77h.

In particular, when the frame pieces 70d and 70e are formed in a symmetrical common shape, the parts management is enhanced, the assembling work is facilitated, and the cost of the mold is reduced because a plurality of types of molds are not required. Can be.
As described above, the side frame according to the present invention may be the side frames 2 and 7 in which a portion having an I-shaped cross section is integrally formed, but may be welded by spot welding or other resistance welding. Side frame 70c.

(Fourth modification)
Next, a side frame 8 according to a fourth modification will be described with reference to FIG.
The side frame 8 is a plate-shaped member having a horizontal cross section that is circular or elliptical, and is arranged such that the rear side portion 81a and the front side portion 83a are connected to the rear side portion 81a and the front side portion 83a so that the thickness direction is the left-right direction. And an intermediate portion 82a.
As described above, the horizontal cross section of the rear side portion 81a and the front side portion 83a is formed in a circular shape or an elliptical shape, and has no edge. For this reason, it is possible to suppress the cushion pad (not shown) that comes into contact with the rear side portion 81a and the front side portion 83a from being deteriorated by friction with the rear side portion 81a and the front side portion 83a.

(Fifth Modification)
The side frames 80 and 80a according to the fifth modification will be described with reference to FIG. Here, FIG. 9A is a cross-sectional view of a side frame 80 having hollow portions 84a and 84b according to a fifth modification, and FIG. 9B is a side frame 80a in which a rear side portion 81c is formed larger than a front side portion 83b. It is sectional drawing.
The side frames 80, 80a include hollow portions 84a, 84c having circular cross sections at the rear portions 81b, 81c, and hollow portions 84b having a circular cross section at the front portions 83b.
The side frames 80, 80a are lighter in weight than the side frames 8 according to the fourth modification because the hollow portions 84a, 84b, 84c are formed.

The side frame 80a is formed such that the rear side portion 81c is formed larger than the front side portion 83b, so that the cross-sectional area on the rear side where a large compressive stress is applied can be increased, and the rigidity can be increased.
The I-shaped cross section according to the present invention means that both end portions have a cross-sectional shape larger than the middle portion, and in addition to the side frame 2 according to the first embodiment, as in this example, It also includes one having a circular rear section 81a and a front section 83a.

(Sixth modification)
Next, a side frame 9 according to a sixth modification will be described with reference to FIG.
The side frame 9 is a frame in which two frame pieces 90a and 90b, which are sheet metals, are joined so as to be back to back and extend vertically.

Specifically, the frame piece 90a includes an intermediate plate 92a extending linearly in the front-rear direction in the horizontal cross section, a front plate 93a formed at the front end of the intermediate plate 92a and having an arc-shaped cross section, and formed at the rear end of the intermediate plate 92a. And a rear side plate 91a having an arc-shaped cross section, and extends in the vertical direction.
Similarly, the frame piece 90b is formed at the front end of the intermediate plate 92b, which extends linearly in the front-rear direction in the horizontal cross section, at the front end of the intermediate plate 92b, and at the rear end of the intermediate plate 92b. And a rear side plate 91b having a circular arc cross section, and extends in the up-down direction.
Each of the frame pieces 90a and 90b constituting the side frame 9 is such that the rear plate 91a and the rear plate 91b and the front plate 93a and the front plate 93b are arranged on the same true circle or ellipse circumference in a horizontal cross section. It is formed so that. Then, the frame pieces 90a and 90b are welded by the spot welding portion 94 in a state where the intermediate plates 92a and 92b face each other.

  In particular, a gap c is formed between the front end of the front plate 93a and the front end of the front plate 93b, and between the rear end of the rear plate 91a and the rear end of the rear plate 91b. By forming the gap c in this way, it is possible to avoid interference between the both ends due to dimensional errors when assembling before spot welding, and to generate abnormal noise due to contact by a load from a seated person. Occurrence can be prevented. Note that a part or the entire range of both ends may be welded by welding without forming the gap c.

  In the above-described embodiment, the side frame of the seat back is formed in an I-shape, the lightening holes are formed, and the braces are formed. However, such a configuration is not limited to the side frame of the seat back, and can be similarly applied to the side frame of the seat cushion.

<< Third Embodiment >>
A seat back frame 1 according to a third embodiment of the present invention will be described with reference to FIGS. Here, FIG. 11 is an overall perspective view showing the seat back frame 1 according to the present embodiment, and FIG. 12 is a rear view of the seat back frame 1.

  The upper frame 3 constituting the seat back frame 1 corresponds to a connection frame according to the present invention, and includes a substantially trapezoidal rear plate 30 and a front plate 31 having substantially the same outer shape as the rear plate 30. It is configured to be overlapped at intervals. Specifically, the upper frame 3 is superimposed on the front and rear plates 31 by forming a hollow inside the rear plate 30 and the front plate 31 by a side edge portion 31k described later and a joint portion 31f described later. The left and right side frames 2 are welded to the upper frame 3 while being inserted into the left and right ends of the upper frame 3 from below and sandwiched back and forth.

  As shown in FIG. 12, the rear plate 30 has a triangular lightening hole 30a formed at the lower center, and an inverted triangular lightening hole 30b formed at the upper center. By forming the lightening holes 30a and 30b as other lightening holes in this way, the weight of the rear plate 30 is reduced.

In the front side plate 31, as shown in FIG. 11, a triangular lightening hole 31a is formed at the center lower side, and an inverted triangular lightening hole 31b is formed at the upper center. Both the lightening holes 31a and 31b are formed at positions overlapping the lightening holes 30a and 30b of the rear plate 30 in the front-rear direction.
Further, the front plate 31 has lightening holes 31a, 31b, 31c, and 31d as other substantially triangular lightening holes divided by braces 31e formed in an X-shape continuously with the front plate 31. Is formed. In other words, the bracing 31e corresponding to the erection part according to the present invention is erected beyond the lightening holes 31a, 31b, 31c, 31d.

  In particular, the braces 31e extend in an X-shape toward the lower two corners 31h and the upper two corners 31i of the upper frame 3. With the formation of the braces 31e in this way, when an external force is applied to the braces 31e, a reaction force is generated from the corners 31h and 31i, so that bending of the braces 31e can be suppressed. .

  A peripheral edge (side edge) other than the lower edge of the front plate 31 is formed with a side edge portion 31k bent toward the rear plate 30, and the side edge portion 31k and the rear plate 30 are welded. I have.

Two notches 31j are formed in the upper part of the front plate 31, and the guide holder 5 protrudes upward from the notch 31j.
The guide holder 5 is a member into which a part of a headrest frame (not shown), which forms a skeleton of a head of a vehicle seat (not shown), is inserted and supported by the rear plate 30 and the front plate 31. Are joined to each other while being sandwiched between them.
In particular, as shown in FIG. 11, when the guide holder 5 is disposed in a portion of the upper frame 3 that overlaps the braces 31e and has high rigidity, the joining of the guide holder 5 can be stabilized.
In the above description, the braces 31e are formed on the front plate 31. However, the rear plates 30 may be formed with braces and lightening holes in the same manner as the front plate 31. Good.

Next, the joining of the rear plate 30 and the front plate 31 and the joining of the upper frame 3 and the side frame 2 will be described with reference to FIGS. 13 and 14A to 14C.
Here, FIG. 13 is a perspective view showing a joint between the rear plate 30 and the front plate 31 and a joint between the upper frame 3 and the side frame 2, and FIGS. It is a schematic diagram which shows an example of the joint part of the front side plate 31.

  At the lower end of the front plate 31, a joint portion 31f for joining with the rear plate 30 is formed. The joint portion 31f is bent and extended rearward at an angle of about 90 degrees from the front surface of the front plate 31 at the lower end of the front plate 31 and is welded to the rear plate 30. The front plate 31 and the rear plate 30 are joined by the joint 31f. As described above, since the joint portion 31f extends from the lower end of the front plate 31, a separate member for joining the rear plate 30 and the front plate 31 becomes unnecessary.

  In particular, as shown in FIG. 14A, the joint portion 31f is bent at the front side from the front plate 31 and is welded to the rear plate 30 at the rear side. The joint 31f is not bent from the rear plate 30 and welded to the front plate 31 on the front side, as in the joint 30g shown in FIG. 14B. For this reason, it is possible to prevent the cushion pad (not shown) from coming into contact with the welded portion on the front side where the repeated load from the occupant is applied, and to make the smooth bent portion come into contact with the cushion pad, thereby preventing the cushion pad from being damaged. Can be prevented.

  Further, as shown in FIG. 14C, the joining portion 31g extends from the front plate 31 and the joining portion 30h extends from the rear plate 30 to a position opposed to the joining portion 31g, and the joining portion 31g and the joining portion 30h May be welded to each other. In other words, if the joint 31g and the joint 30h are welded to the position where the joint 31f shown in FIG. 14A is formed, the edges of the weld are not generated on both the front side and the rear side, so that the cushion pad Damage can be further prevented.

  In particular, the joint 31f is formed near the corner 31h at the lower end of the brace 31e, as shown in FIG. For this reason, the rigidity in the vicinity of the joint portion 31f where stress tends to concentrate due to the joint portion can be increased by the braces 31e, and the torsional rigidity of the upper frame 3 can be increased.

  The I-shaped left and right side frames 2, as shown in FIG. 13, are left and right ends of the upper frame 3 and are inserted between the rear plate 30, the front plate 31, and the side edge portion 31k. It is welded and combined with the upper frame 3 to form a closed cross-sectional shape. The rigidity of the connecting portion between the side frame 2 and the upper frame 3 is increased by being formed in this manner. Furthermore, since the brace 31e extends at this connection portion, the rigidity of the connection portion between the rear plate 30 and the front plate 31 where stress tends to concentrate can be secured by the brace 31e.

The above embodiments are merely examples for facilitating the understanding of the present invention, and do not limit the present invention. The present invention can be changed and improved without departing from the gist thereof, and it is needless to say that the present invention includes equivalents thereof.
In particular, it is optional to combine or delete the features described in each embodiment or the features described in each modification.

  The bracing as the erection portion according to the present invention has been described as having an X shape in a front view, but the present invention is not limited to this shape. For example, the erection part has a shape in which “X” and “I” overlap (a shape), a shape in which “X” and “+” overlap (a rice shape), and a shape in which “X” and “−” overlap. In addition, it is possible to adopt an arbitrary shape such as a C-shape, and it is possible to bridge over the lightening hole so as to connect at least any two of the upper, lower, left and right portions of the upper frame. Just fine.

1,1a Seat back frame (seat frame)
2, 7, 70, 70a, 70b, 8, 80, 80a, 9 Side frame 2a, 7a Upper part 2b, 7b, 7c Lower part 21, 21a, 21b Rear side part 22, 22, a, 22b Middle part 22d Lightening hole 22e, 22f Bracing 22g Mounting holes 23, 23a, 23b Front side 24 Fillet 70d, 70e, 90a, 90b Side frame pieces 71, 71a, 71b, 71c, 71d, 71e, 71f, 75 Rear side 72, 72a, 72b, 72b, 76 Intermediate portions 73, 73a, 73b, 73c, 73d, 73e, 77 Front side 74 Fillet 75g, 75h Rear side plate 76g, 76h Intermediate plate 77g, 77h Front side plate 78 Spot welded portions 81a, 81b, 81c Rear side 82a Intermediate part 83a, 83b Front part 84a, 84b, 84c Hollow part 91 Rear part 91a, 91b Rear Side plate 92 Intermediate portion 92a, 92b Intermediate plate 93 Front side portion 93a, 93b Front side plate 94 Spot welded portion 3 Upper frame (connection frame)
30 Rear plate 30a, 30b Lightening hole (other lightening hole)
30d, 30f Joint 30g, 30h Joint 31 Front plate 31a, 31b, 31c, 31d Lightening hole (other lightening hole)
31e bracing (construction part)
31f, 31g Joint 31h, 31i Corner 31j Notch 31k Side edge 4 Lower frame 5 Guide holder c Clearance da, db, dc, dd, de Front / rear width f Width q Hardening

Claims (15)

A seat frame comprising a left and right side frame having an I-shaped cross section extending in a longitudinal direction and forming a skeleton of a seat,
The side frame has both end portions at both ends in a short direction orthogonal to the longitudinal direction and the sheet width direction, and an intermediate portion between the both end portions,
The seat frame is a seat back frame,
The side frame extends in a vertical direction as the longitudinal direction,
The short direction is a front-back direction,
The two end portions include a front side portion and a rear side portion,
The longitudinal dimension of the upper front side portion or the rear side portion of the upper side frame is smaller than the longitudinal dimension of the lower front side portion or the rear side portion of the lower side frame. Seat frame. The length of the both ends in the sheet width direction is larger than the length of the intermediate portion in the sheet width direction,
2. The seat frame according to claim 1, wherein a lightening hole formed in the seat width direction and a brace crossing the lightening hole are formed in the intermediate portion. 3. The seat frame according to claim 1, wherein the upper and lower portions of the side frame have substantially equal dimensions in the front-rear direction.   2. The seat frame according to claim 1, wherein a dimension in the seat width direction at any one of the both ends is larger than a dimension in the short direction at the end. 3.   2. The seat frame according to claim 1, wherein a dimension in the lateral direction at any one of the two end portions is larger than a dimension in the seat width direction at the intermediate portion. 3.   2. The seat frame according to claim 1, wherein a cross section of the both ends of the side frame has a circular or elliptical shape. 3. The length of the side frame in the front-rear direction is shorter at the upper part than at the lower part,
A front-to-rear width of the front portion or the rear portion at the upper portion of the side frame is larger than a front-to-rear width of the front or rear portion at the lower portion of the side frame. The seat frame according to claim 1.   The seat frame according to claim 7, wherein the side frame is hardened only in the upper portion having a shorter length in the front-rear direction. The seat frame according to claim 2 , wherein a plurality of the braces are formed, and at least two of the braces extend away from each other toward the rear of the seat. 4. The seat frame, a connecting frame for connecting the left and right side frames is composed of a front side plate and the rear plate,
At least one of the front plate and the rear plate has another lightening hole penetrating in the front-rear direction, and a erection portion erected beyond the other lightening hole,
The seat frame according to claim 1, wherein the front plate and the rear plate are joined at a lower edge of the connection frame.   11. The seat frame according to claim 10, wherein the front plate and the rear plate are joined near an end of the bridging portion of the lower edge of the connection frame. 12.   The seat frame according to claim 10, wherein the bridge portion extends at a corner of the connection frame.   The seat frame according to claim 10, wherein the bridging portion extends toward a connection portion of the connection frame with the left and right side frames. One side edge portion of the front plate or the rear plate extends toward the other to bend and is joined to the other,
A portion where the left and right side frames and the connection frame are connected forms a closed cross-sectional shape by being surrounded by the front plate, the rear plate, and the side edge portion. Item 11. The seat frame according to item 10. A guide holder for supporting a part of the headrest frame is attached to the connection frame,
The guide holder is disposed between the front plate and the rear plate,
The seat frame according to claim 10, wherein a part of the bridging portion is disposed so as to overlap with the guide holder in the front-rear direction.

Images