Back frame

Abstract

An example of a back frame capable of suppressing deformation when an external force acts to twist the side frame is disclosed. [Solution] The first joint W1 to the third joint W3 are provided on the front and rear sides of the hinge center 7C of the recliner 7A, and the hinge center 7C is located within a polygon (shown as a figure with thick dashed lines) connecting the first joint W1 to the third joint W3. As a result, in the back frame, when an external force acts on the first side frame 3 in a way that twists the first side frame 3, the lower beam 6 receives the torsional torque generated in the first side frame 3 as tensile and compressive forces. Therefore, deformation that would cause the first side frame 3 to twist significantly can be suppressed.

Description

Technical Field

[0001] The present disclosure relates to a back frame used for a seat back of a vehicle seat.

Background Art

[0002] For example, the back frame described in Patent Document 1 is configured to include a round pipe bent in a U-shape, and a pipe or the like that extends in the seat width direction and connects the portions extending in the vertical direction of the round pipe.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The present disclosure discloses an example of a back frame capable of suppressing deformation when an external force acts to twist a portion extending in the vertical direction (hereinafter referred to as a side frame) of the back frame. Note that the "deformation that twists the side frame" refers to, for example, a torsional deformation centered on a virtual axis that passes through the center of the cross section of the side frame and extends along the extending direction of the side frame.

Means for Solving the Problems

[0005] The back frame used for the seat back of a vehicle seat preferably includes at least one of the following constituent elements, for example. In other words, the constituent elements are a first side frame (3) positioned at one end in the seat width direction and extending vertically, a second side frame (4) positioned at the other end in the seat width direction and extending vertically, a first connecting member (5) extending in the seat width direction and connecting the upper end of the first side frame (3) and the upper end of the second side frame (4), a recliner (7A) constituting a hinge mechanism for changing and maintaining the angles of the first side frame (3) and the second side frame (4), the recliner (7A) being joined and fixed to at least the lower end of the first side frame (3), and a second connecting member (6) extending in the seat width direction and connecting the lower end of the first side frame (3) and the lower end of the second side frame (4).

[0006] The second connecting member (6) is joined to the first side frame (3) on the front and rear sides, with the hinge center (7C) of the recliner (7A) in between. Furthermore, a virtual figure connecting the joints between the second connecting member (6) and the first side frame (3), projected onto a virtual plane perpendicular to the seat width direction, is a polygon, and the hinge center (7C) projected onto this virtual plane is located within the polygon projected onto this virtual plane.

[0007] As a result, in the back frame, when an external force acts on the first side frame (3) in such a way that it twists the first side frame (3), the second connecting member (6) and the first side frame (3) are joined together, and therefore the second connecting member (6) receives the torsional torque generated in the first side frame (3) as tensile and compressive forces.

[0008] Furthermore, since torsional deformation is a type of shear deformation, and generally, tensile and compressive deformations can suppress deformation more effectively than shear deformation, deformations that cause a large twist in the first side frame (3) can be suppressed compared to a configuration that relies solely on shear stress to counteract the torsional deformation.

[0009] The back frame may also have the following configuration, for example: In other words, the cross-sectional shape of the longitudinal middle portion of the second connecting member (6) is preferably a roughly C-shape with the upper side open. Furthermore, the length of the joint located on the rear side of the hinge center (7C) is preferably longer than the length of the joint located on the front side of the hinge center (7C).

[0010] Incidentally, the symbols in each of the parentheses above are just examples showing the correspondence with the specific configurations etc. described in the embodiments described later, and this disclosure is not limited to the specific configurations etc. indicated by the symbols in the parentheses above. [Brief explanation of the drawing]

[0011] [Figure 1] This is a diagram showing the back frame according to the first embodiment. [Figure 2] This is a diagram showing the upper part of the back frame according to the first embodiment. [Figure 3] This is a diagram showing the back frame according to the first embodiment. [Figure 4] This is a diagram showing the lower beam portion according to the first embodiment. [Figure 5] This diagram shows the connection structure between the lower beam and the first side frame. [Figure 6] This diagram shows the connection structure between the lower beam and the first side frame. [Figure 7] This diagram shows the connection structure between the lower beam and the first side frame. [Modes for carrying out the invention]

[0012] The following "Embodiments of the Invention" are examples of embodiments that fall within the technical scope of this disclosure. In other words, the features defining the invention as described in the claims are not limited to the specific configurations and structures shown in the embodiments below.

[0013] This embodiment is an example in which the back frame according to the present disclosure is applied to a seat mounted on a vehicle such as an automobile (hereinafter referred to as a vehicle seat). Arrows, diagonal lines, etc. indicating directions attached to each figure are described to facilitate understanding of the relationship between each figure and the shape of members or parts.

[0014] Therefore, the back frame is not limited to the directions attached to each figure. The directions shown in each figure are the directions in the state where the vehicle seat according to the present embodiment is assembled to the vehicle. The figure with diagonal lines does not always show a cross-sectional view.

[0015] At least the members or parts described with reference numerals are provided with at least one, unless otherwise specified such as "one". That is, when there is no such specification as "one", two or more of the members may be provided. The back frame shown in the present disclosure includes at least one of the components such as the members or parts described with reference numerals and the illustrated structural parts.

[0016] (First Embodiment) <1. Outline of Back Frame> As shown in FIG. 1, the back frame 1 according to the present embodiment is an example of a frame used for the seat back of a rear seat of a vehicle. Specifically, the back frame 1 is a frame used for the right seat of the rear seat where three people can ride.

[0017] The seat back is a part for supporting the back of the seated person. The back frame 1 is a member constituting the skeleton of the seat back. Incidentally, a frame 2 for the middle seat is connected to the back frame 1.

[0018] The frame 2 for the middle seat includes a tower frame 2A, a first connecting frame 2B, a second connecting frame 2C, and the like. The tower frame 2A is a strength member extending in the vertical direction. The first connecting frame 2B and the second connecting frame 2C are strength members for connecting the tower frame 2A to the back frame 1.

[0019] <2. Details of the Back Frame> <2.1 Structure of the Back Frame> The back frame 1 includes at least a first side frame 3, a second side frame 4, an upper beam portion 5, a lower beam portion 6, a first recliner 7A, a second recliner 7B, and a back panel (not shown).

[0020] The first side frame 3 is a strength member disposed on one end side in the seat width direction (the left end side in this embodiment) and extending in the vertical direction. The second side frame 4 is a strength member disposed on the other end side in the seat width direction (the right end side in this embodiment) and extending in the vertical direction.

[0021] The upper beam portion 5 is an example of a first connecting member, and as shown in FIG. 3, it is an upper panel that extends in the seat width direction and connects the upper end sides of the first side frame 3 and the second side frame 4. The upper beam portion 5 is configured to have a substantially U-shaped or substantially C-shaped cross-sectional shape with the rear side open (see FIG. 2).

[0022] The lower beam portion 6 is an example of a second connecting member, and as shown in FIG. 3, it is a lower panel that extends in the seat width direction and connects the lower end sides of the first side frame 3 and the second side frame 4. The first side frame 3, the second side frame 4, the upper beam portion 5, and the lower beam portion 6 constitute a rectangular frame body.

[0023] The back panel (not shown) is a plate-like member disposed on the back side of the frame body and covering the entire back of the frame body. In addition to the back of the frame body, the back panel according to this embodiment also covers the back of the frame 2 for the center seat.

[0024] As shown in FIG. 1, a retractor 9 is fixed below the upper beam portion 5 of the back panel. The retractor 9 is a device for winding up the seat belt 10. A belt receiving portion 5A is provided on the upper beam portion 5.

[0025] The belt receiving portion 5A is a through-hole through which the seat belt 10 is inserted. When tension T is generated in the seat belt 10, the belt receiving portion 5A receives that tension T. In other words, the tension T is input to the frame body via the upper beam portion 5.

[0026] The first recliner 7A and the second recliner 7B are devices that constitute a hinge mechanism for changing and maintaining the angle of the back frame 1. Specifically, one side of the first recliner 7A is welded to the lower end of the first side frame 3, and the other side is fixed to the vehicle via a bracket 11A.

[0027] The second recliner 7B is joined and fixed to the lower end of the second side frame 4 by welding on one side, and fixed to the vehicle via a bracket 11B on the other side. Incidentally, the "one side" mentioned above is the "right side" in this embodiment, and the "other side" mentioned above is the "left side" in this embodiment.

[0028] <2.2 Detailed Structure of the Lower Beam Section> As shown in Figure 4, the lower beam section 6 includes a front panel section 61, a rear panel section 62, and a bottom panel section 63. The front panel section 61, the rear panel section 62, and the bottom panel section 63 are integrally formed from a single steel plate through press working.

[0029] Furthermore, the longitudinal middle section of the lower beam 6 is configured with a roughly C-shaped cross-section that opens upwards. The longitudinal middle section of the lower beam 6 refers to a predetermined range that includes the longitudinal center (midpoint) of the lower beam 6.

[0030] The longitudinal middle portion of the front panel 61 has a concave shape that is recessed towards the rear, so that it is located further rearward than one end and the other end of the front panel 61 in the longitudinal direction. This concave shape is intended to avoid interference with the seated person's buttocks.

[0031] The rear panel section 62 is provided with a beam section 62A that extends in the width direction of the sheet. The beam section 62A is composed of protrusions that project in the front-rear direction of the sheet and extend in the width direction of the sheet. Therefore, the beam section 62A functions as a reinforcing part that improves the bending rigidity of the rear panel section 62.

[0032] Furthermore, one longitudinal end of the lower beam 6 is welded to the lower end of the first side frame 3. The other longitudinal end of the lower beam 6 is welded to the lower end of the second side frame 4. In this embodiment, the lower beam 6 is joined to each of the side frames 3 and 4 by laser welding.

[0033] <2.3 Joint structure between the lower beam and the side frame> The following description concerns the connection structure between the lower beam 6 and the first side frame 3. Since the connection structure between the lower beam 6 and the first side frame 3 is the same as that between the lower beam 6 and the second side frame 4, the description of the connection structure between the lower beam 6 and the second side frame 4 is omitted.

[0034] As shown in Figure 5, the lower beam section 6 is provided with a first joint W1, a second joint W2, a third joint W3, and the like. The first joint W1 is the joint located on the front side of the hinge center 7C of the recliner 7A.

[0035] The second joint W2 and the third joint W3 are located on the rear side of the hinge center 7C. The length of the joint located on the rear side of the hinge center 7C is longer than the length of the joint located on the front side of the hinge center 7C.

[0036] The joint length of the joint located on the rear side is the sum of the joint length of the second joint W2 and the joint length of the third joint W3. The joint length of the joint located on the front side is the joint length of the first joint W1.

[0037] Furthermore, the virtual figure connecting the first joint W1 to the third joint W3, when projected onto a virtual plane perpendicular to the sheet width direction, becomes a polygon (a quadrilateral in this embodiment), as shown by the thick dashed line in Figure 6. Moreover, the hinge center 7C projected onto the virtual plane is located within the polygon (the figure shown by the thick dashed line) projected onto the virtual plane.

[0038] Furthermore, the virtual figure connecting the first joint W1 to the third joint W3, that is, the figure connecting multiple joints, refers to the figure formed when the ends of each joint are connected by a virtual straight line. The ends of the joints, that is, the ends of the joints, refer to the ends of the outer shape of the joints when viewed macroscopically.

[0039] In this embodiment, laser welding is employed as the joining method. Therefore, the end of the joining point (joint) specifically refers to the welding mark left by laser welding. Accordingly, the end of the joint according to this embodiment refers to the end of the welding mark.

[0040] Incidentally, if the joint, or weld mark, is curved macroscopically, the virtual shape connecting the multiple joints will be a polygon with rounded corners. Also, if the welding method is spot welding, the virtual shape connecting the multiple point-like joints (weld marks) will be the virtual shape connecting the multiple joints.

[0041] <3. Features of the back frame according to this embodiment> When tension T is generated in the seat belt 10, the back frame 1 receives this tension T at the belt receiving portion 5A. As a result, as shown in Figure 7, a stress is generated in the first side frame 3 that induces a twisting deformation of the first side frame 3 around the hinge center 7C.

[0042] In contrast, in the back frame 1 according to this embodiment, the first joint W1 is located on the front side of the first side frame 3, and the second joint W2 and the third joint W3 are located on the rear side of the first side frame 3.

[0043] As a result, even if stress occurs in the back frame 1 that induces a twisting deformation of the first side frame 3, the lower beam 6 and the first side frame 3 are joined at the first joint W1 to the third joint W3, so the lower beam 6 receives the torsional torque M generated in the first side frame 3 as a tensile force F1 and a compressive force F2.

[0044] Furthermore, since torsional deformation is a type of shear deformation, and generally, tensile and compressive deformations can suppress deformation more effectively than shear deformation, this configuration can suppress deformations that cause the first side frame 3 to twist significantly, compared to a configuration where the torsional deformation is counteracted solely by the shear stress generated in the first side frame 3.

[0045] Furthermore, the hinge center 7C projected onto the virtual plane is located within the polygon projected onto that virtual plane (shown as a thick dashed line in Figure 6). This makes it possible to reliably ensure torsional rigidity around the hinge center 7C.

[0046] (Other embodiments) In the embodiments described above, the first joint W1, the second joint W2, and the third joint W3 were joined by welding. However, this disclosure is not limited thereto. That is, the disclosure may also include a configuration in which the parts are joined by, for example, an adhesive.

[0047] In the embodiments described above, the back frame 1 had a metal back panel. However, the disclosure is not limited thereto. That is, the disclosure may also include, for example, a back frame without a back panel, or a back frame having a resin back panel.

[0048] In the embodiments described above, the retractor 9 was fixed to a metal back panel. However, the disclosure is not limited thereto. That is, the disclosure may also include, for example, a configuration without a retractor 9, or a configuration in which the retractor 9 is fixed to a side frame or upper beam.

[0049] The lower beam portion 6 according to the above embodiment was configured with a roughly C-shaped cross-section that was open at the top. However, the disclosure is not limited thereto. That is, the disclosure may, for example, consist of a front panel portion 61 and a rear panel portion 62 which are composed of independent parts, and the lower beam portion 6 may be composed of these two parts 61 and 62.

[0050] In the embodiments described above, the vehicle seat according to this disclosure was applied to a vehicle. However, the application of the invention disclosed herein is not limited to this. That is, the disclosure can be applied, for example, to seats used in vehicles such as railway cars, ships and aircraft, as well as to stationary seats used in theaters, homes, etc.

[0051] Furthermore, this disclosure is not limited to the embodiments described above, but is sufficient to be consistent with the intent of the disclosures described in the embodiments described above. Therefore, it may be a configuration in which at least two of the embodiments described above are combined, or a configuration in which any of the illustrated components or components described with reference numerals in the embodiments described above are omitted. [Explanation of Symbols]

[0052] 1… Back frame 3… First side frame 4… Second side frame 5… Upper beam part 6… Lower beam part 7A, 7B... Reclining seats 9… Retractor 10… Seat belt 11A… Bracket 11B… Bracket W1... 1st joint W2… Second joint W3... 3rd joint

Claims

1. In a back frame used for the seat back of a vehicle seat, A first side frame is positioned at one end in the width direction of the seat and extends in the vertical direction, A second side frame is positioned on the other end in the width direction of the seat and extends in the vertical direction, A first connecting member extending in the width direction of the sheet and connecting the upper end of the first side frame and the upper end of the second side frame, A recliner comprising a hinge mechanism for changing and maintaining the angles of the first side frame and the second side frame, the recliner being joined and fixed to at least the lower end side of the first side frame, It includes a second connecting member that extends in the width direction of the sheet and connects the lower end of the first side frame and the lower end of the second side frame, The second connecting member is joined to the first side frame on the front and rear sides, with the hinge center of the recliner in between. Furthermore, a virtual figure connecting the joint between the second connecting member and the first side frame, wherein the figure projected onto a virtual plane perpendicular to the sheet width direction is a polygon, and the hinge center projected onto the virtual plane is located within the polygon projected onto the virtual plane.

2. The back frame according to claim 1, wherein the cross-sectional shape of the longitudinal middle portion of the second connecting member is substantially C-shaped with an open upper side.

3. The back frame according to claim 1 or 2, wherein the joining length of the joining portion located on the rear side of the hinge center is longer than the joining length of the joining portion located on the front side of the hinge center.

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