Note: Descriptions are shown in the official language in which they were submitted.
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TITLE OF THE INVENTION
SEAT BACK FRAME
FIELD OF THE INVENTION AND RELATED ART STATEMENT
The present invention relates to an automotive seat
and, more particularly, to a construction of a seat back
frame .
To tilt back a seat back for an automotive seat, a
reclining device is provided at the side of a connecting
portion between a seat and its seat back. The reclining
device is available in two types: a double reclining system
in which the reclining devices are provided on both sides of
the seat and a single reclining system in which the reclining
device is provided only on one side of the seat.
Therefore, the frame shape of seat backs differs
between the double reclining system and the single reclining
system depending on whether or not the reclining device
installation portions are present on the opposite sides of
the seat. More specifically, the double reclining seat back
frame has basically the same shape on the right and left
sides because the reclining device installation portions are
present on both sides. As shown in FIG. 16, for the single
reclining seat back frame 31, one side frame is provided with
a reclining device installation bracket 32, and the other
side frame 33 is merely provided with a free hinge hole 34 at
the end thereof. In FIG. 16, reference numeral 33a denotes a
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retainer welded to the side frame 33, and 33b denotes a hook
provided on the installation bracket 32.
FIG. 17 shows a side frame 36 for a double reclining
seat back frame. As shown in the figure, the side frame 36
is provided with a bead 39 for absorbing a load at an
arbitrary place between an installation hole 37 for the
reclining device installation bracket and a lower pipe 38.
For example, when an external force is applied to a passenger
sitting on the seat and thereby a backward load is applied to
the seat back frame, the frame is deformed plastically at the
portion of the bead 39, whereby the load applied to the
reclining device is controlled.
Also, for the side frame 36 shown in FIG. 17, when an
upper pipe 40 is fixed as shown in FIG. 18, the hatched
portion shown in FIG. 17 is sometimes cut to adjust the
height of seat back frame. In such a case, in order to fix
the upper pipe 40 to the side frame 36, the upper end shape
of the side frame 36 must coincide with the outer periphery
of the upper pipe 40. For this purpose, the upper end
portion of the side frame 36 must have the same shape for a
certain length.
As described above, since the shape of seat back frame
differs between the double reclining system and the single
reclining system, the seat back frames of two systems must be
manufactured separately, resulting in poor production
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efficiency.
As described above, the double reclining seat back
frame is provided with a bead on the right and left side
frames to absorb load energy by the plastic deformation of
side frames at the bead portion.
However, although the side frame is deformed under a
predetermined load, the time for which the deformation of the
side frame can be controlled is very short because the side
frame is bent at the small bead portion. Also, because the
frame faces of the right and left side frames are parallel to
the longitudinal direction of vehicle body, when the bead is
crushed and then the deformation of frame further proceeds,
there is no knowing to which direction of right and left the
side frame falls, and the strength balance of side frame and
upper pipe is destroyed, so that the upper pipe is sometimes
deformed. Because the portion at which the bead is formed
lies between the lower pipe and the installation hole for
reclining device, if a frame torsion occurs after the bead is
crushed, there is a possibility that the reclining device is
deformed.
For the single reclining seat back frame, the same bead
cannot be formed on the right and left side frames because
the shapes of the right and left side frames are different.
Moreover, since the side on which the reclining device
installation bracket is provided has a high strength, the
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side frame on the free hinge side is sometimes distorted
when a backward load is applied to the seat back frame.
OBJECT AND SUMMARY OF THE INVENTION
The object of an aspect of the present invention is
to solve the above problems, and accordingly an object
thereof is to provide a seat back frame in which the same
frame can be used for both of single reclining and double
reclining, the right and left side frames have the equal
strength, and the deformation of side frame can be
controlled.
To achieve the above object, a first aspect of the
present invention provides a seat back frame in which a
reclining installation portion is provided on right and
left side frames of a seat back for an automotive seat
and an upper frame connecting the upper ends of the right
and left side frames and a lower frame connecting the
lower ends thereof are provided, characterized in that a
reclining device is fitted at only one of the reclining
installation portions on the right and left side frames,
and the other reclining installation portion thereof is
fitted with a free hinge metal with which a single
reclining seat is supported by a frame for double
reclining seat.
Also, a second aspect of the present invention
provides a seat back frame in which a reclining
installation portion is provided on right and left side
frames of a seat back for an automotive seat and an upper
frame connecting the upper
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ends of the right and left side frames and a lower frame
connecting the lower ends thereof are provided, characterized
in that on a face of the respective right and left side
frames, a triangular plane in which two sides of triangle
extend from one side of the side frame face to the other side
thereof and the remaining one side forms the side of the side
frame face is provided, and a bent plane is formed by
combining the triangular planes so as to be vertically
adjacent to each other, by which the right and left side
frames are deformed at the boundary line of the triangular
planes by a backward load applied to the seat back.
Also, a third aspect of the present invention provides
a seat back frame in which a reclining installation portion
is provided on right and left side frames of a seat back for
an automotive seat and an upper frame connecting the upper
ends of the right and left side frames and a lower frame
connecting the lower ends thereof are provided, characterized
in that a reclining device is fitted to only one of the
reclining installation portions on the right and left side
frames, and the other reclining installation portion thereof
is fitted with a free hinge metal, the right and left side
frames are shaped so as to be wider in front, a triangular
plane in which two sides of triangle extend from one side of
the side frame face to the o-ther side thereof and the
remaining one side forms the side of the side frame face is
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provided, a bent plane is formed by combining the
triangular planes so as to be vertically adjacent to each
other, the bending of the bent plane is alternate, the
ends of the lower frame are fixed to the right and left
side frames at a position between the triangular plane
and the reclining installation portion, the respective
right and left side frames are provided with a curved
portion with the same shape as that of the outer
periphery of the upper frame fixed to the upper portions
of the right and left side frames, and an L-shaped hook
is provided at the side of the respective right and left
side frames.
In accordance with one embodiment of the present
invention, a seat back frame for a seat back of an
automotive seat, comprises:
right and left side frames each including a
reclining installation portion adapted for attaching
a reclining device to the respective side frame;
an upper frame connecting the upper ends of the
right and left side frames; and
a lower frame connecting the lower ends of the
right and left side frames;
each of the right and left side frames having a
face which includes at least two triangular planes,
each of the triangular planes having two sides which
extend from one edge of the respective side frame
face to the other edge thereof and the remaining
side of each triangular plane forming a portion of
one of the edges of the respective side frame face,
the triangular planes of each side frame face being
vertically adjacent and joined at boundary lines
therebetween and angled with respect to each other
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so as to form a bent plane on each side frame face,
whereby a backward load applied to the seat back
causes the side frames to deform at the bent planes
along the boundary lines between the contiguous
triangular planes of each bent plane.
In accordance with another embodiment of the present
invention, a seat back frame for a seat back of an
automotive seat, comprises:
right and left side frames each including a
reclining installation portion adapted for attaching
a reclining device to the respective side frame, the
side frames being arranged such that the seal back
frame is wider at a front side thereof than at a
rear side thereof, each side frame including an L-
shaped hook attached to a side of the respective
side frame;
an upper frame connecting the upper ends of the
right and left side frames;
a lower frame connecting the lower ends of the
right and left side frames;
a reclining device fitted to the reclining
installation portion of one of the right and left
side frames;
the reclining installation portion of the other
side frame comprising a free hinge portion;
each of the side frames including a curved
portion having a shape that is complementary to the
outer contour of the upper frame, each of the side
frames having a face which includes at least two
triangular planes, each of the triangular planes
having two sides which extend from one edge of the
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respective side frame face to the other edge thereof
and the remaining side of each triangular plane
forming a portion of one of the edges of the
respective side frame face, the triangular planes of
S each side frame face being vertically adjacent and
contiguous and angled with respect to each other so
as to form a bent plane on each side frame face.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a front view of a seat back frame in
accordance with an embodiment of the present invention;
FIG. 2 is a side view of a seat back frame in
accordance with an embodiment of the present invention;
FIG. 3 is a sectional view taken along the line X-X
of FIG. 1;
FIG. 4 is a schematic back view of a side frame for
a seat back frame in accordance with an embodiment of the
present invention;
FIG. 5 is an enlarged sectional view showing a
fixing portion of a side frame and a lower pipe for a
seat back frame in accordance with an embodiment of the
present invention;
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FIG. 6 is a perspective view of a side frame for a seat
back frame in accordance with an embodiment of the present
invention;
FIG. 7 is a perspective view for illustrating a
construction of side frame upper end portion for a seat back
frame in accordance with an embodiment of the present
invention;
FIG. 8 is an enlarged sectional view showing a fixing
portion of a side frame and an upper pipe for a seat back
frame in accordance with an embodiment of the present
invention;
FIG. 9 is a perspective view showing a deformed state
when a torsional load is applied to a seat back frame in
accordance with an embodiment of the present invention;
FIG. 10 is a perspective view showing a fixing portion
of a hook formed on a side frame and an S spring for a seat
back frame in accordance with an embodiment of the present
invention;
FIG. 11 is a perspective view showing a fixing portion
of a hook formed on a side frame and a full mold wire for a
seat back frame in accordance with an embodiment of the
present invention;
FIG. 12 is a perspective view showing a fixing portion
of a hook formed on a side frame and a contour mat for a seat
back frame in accordance with an embodiment of the present
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invention;
FIG. 13 is a perspective view showing a fixing portion
of a hook formed on a side frame and a coil spring for
contour mat for a seat back frame in accordance with an
embodiment of the present invention;
FIG. 14 is a perspective view showing a seat using a
seat back frame in accordance with an embodiment of the
present invention;
FIG. 15 is a sectional view taken along the line Y-Y of
FIG. 14;
FIG. 16 is a perspective view of a conventional seat
back frame;
FIG. 17 is a perspective view of a side frame for a
conventional seat back frame; and
FIG. 18 is a sectional view showing a fixing portion of
a side frame and an upper pipe for a conventional seat back
frame.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
A seat back frame in accordance with an embodiment of
the present invention will be described with reference to the
accompanying drawings.
FIGS. 1 and 2 show a seat back frame 1 in accordance
with the present invention. This seat back frame 1 is mainly
composed of bilaterally symmetrical side frames 2a and 2b, an
upper pipe 3 formed as a U-shaped upper frame welded to both
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upper end portions of the side frames 2a and 2b, a lower pipe
4 formed as a lower frame welded to the lower portions of the
side frames 2a and 2b, and a back plate 5 welded at the lower
part of the upper pipe 3.
The side frame 2a, 2b is formed of a plate of a U shape
in cross section. As shown in FIG. 2, a line connecting AB
to BC at a height positioned at the lap of a passenger is
formed curvedly, and two reclining device installation bolt
holes 7a are formed at the lower end portion. The reclining
device is provided along the side frame 2a, 2b. A
conventional type of reclining device can be used, so that
the explanation of construction thereof is omitted. As shown
in FIG. 3, the side frames 2a and 2b are shaped wider in
front so that the front side 12a is wider than the rear side
12b. As shown in FIG. 2, the face of the side frame 2a, 2b
is provided with triangular planes indicated by triangles
ADB, BCD, and CDE adjoining in the vertical direction of the
side frame 2a, 2b. Each of these triangular planes has two
sides using two out of the sides a to d extending from the
front side 12a to the rear side 12b of the side frame 2a, 2b
and one side on the front side or rear side of the side frame
2a, 2b.
These triangular planes do not~lie on the same plane.
As shown in FIG. 4, a great bent portion is formed on the
common side b of the triangles ADB and HCD, and a bent
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portion is formed on the common side c of the triangles CBD
and CDE. Also, bent portions are formed on the side a of the
triangle ADB and on the side d of the triangle CDE.
As shown in FIGS. 2 and 3, the side frames 2a and 2b
are formed integrally with three sets of L-shaped hooks 6.
These hooks 6 are formed at the same intervals vertically
with the same width, and a retaining hole 6b is formed in an
attaching piece 6a. As shown in FIG. 5, at the lower part of
the side frame 2a, 2b is provided a circular step portion 7b,
to which the lower pipe 4 is welded on the outer side. As
shown in FIG. 2, the step portion 7b is located between the
reclining device installation bolt holes 7a and the side d of
the triangle CDE. As shown in Fig. 5, the end of the lower
pipe 4 slightly protrudes from the step portion 7b, but does
not protrude from the reclining device installation planes
12.
The reclining device installation planes 12 at the
lower parts of the side frames 2a and 2b are not arranged so
as to be wider in front but in parallel to each other as
shown in FIGS. 1 and 5.
As shown in FIG. 6, the end portions of the upper pipe
3 are welded to the upper end portions of the side frames 2a
and 2b. At this fixing portion, as shown in FIGS. 7 and 8, a
recess 8a is formed at the upper part of the side frame 2a,
2b, a vertically long, curved joint portion 8b is provided at
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the rear of the recess 8a, and a non-joint portion 8c is
provided at the front. The diameter of the joint portion 8b
is equal to the outside diameter of the upper pipe 3. For
the non-joint portion 8c, the width g at the lower part is
larger than the width f at the upper end.
As shown in FIG. 1, a pair of headrest attachment
pieces 10 are provided at the upper part of the upper pipe 3,
and a back plate 5 is welded to both the lower end portions
of the upper pipe 3.
The following is a description of the operation and
effects of the seat back frame.
In this embodiment, since both of the side frames 2a
and 2b of the seat back frame 1 can be fitted with a
reclining device, this seat back frame can be used for a
double reclining seat. Also, by installing a reclining
device to only one side of the seat back frame 1 and by
making the other side a free hinge, the seat back frame can
be used as a single reclining seat. Thereupon, the same seat
back frame 1 can be used for both of single reclining seat
and double reclining seat. Therefore, the seat back frame of
the same shape can be produced in large quantities, resulting
in a decrease in production cost.
Since a great bend portion is formed by the triangular
planes ABD and BCD as shown in FIG. 2 and the side frames 2a
and 2b are arranged so as to be wider in front, the bent
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portion and tilting direction of the side frame can be
restricted when a backward load is applied to the seat back
frame 1.
That is, when the side frame 2a, 2b is bent, the
triangular planes ABD, HCD, and CDE are bent on the common
sides b and c, and the areas of the triangular planes AHD,
BCD, and CDE are large. Therefore, the range of time for
which the load input can be controlled is widened, a heavy
load can be received for a long time, and no sudden moment
change occurs during deformation.
In FIG. 6, the direction in which the side frame 2a, 2b
is bent is indicated by arrows. As shown in the figure, the
side frame 2a, 2b is bent in the arrow-marked direction on
the sides a, c, and d of the triangles, and the side b is
bent to the inner side of the side frame 2a, 2b. Therefore,
the seat back frame 1 is deformed backward. By this load
control, the upper pipe 3 and the side frame 2a, 2b are
balanced in terms of strength, so that the torsion of the
upper pipe 3 can be decreased.
Thus, when the side frame 2a, 2b is deformed by a load,
the deformation takes place at the upper part above the side
d of the triangular plane CDE. Therefore, on the reclining
device installation plane 12, a deformation does not occur,
so that the reclining device. is not affected by the load.
FIG. 9 shows a deformed state of the seat back frame 1
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in which the side frame 2a is the free hinge side and the
side frame 2b is fitted with a reclining device so as to be
used for a single reclining seat. As shown in the figure,
when the side frame 2b on the reclining device installation
side is subjected to a torsion indicated by arrow by a load
such that the free hinge side of the side frame 2a is
twisted, the deformation of the side frame 2b is started by
the bending of the side a of the side frame 2b. In this case
as well, the deformation takes place at the portion above the
side d, so that the influence of torsion on the free hinge
side is less liable to be transmitted to the reclining device
installation plane 12.
In the case where the seat back height is adjusted when
the upper pipe 3 is installed to the side frames 2a and 2b of
the seat back frame 1, the upper end portions of the side
frames 2a and 2b are cut. In such a case, since a vertically
long joint portion 8b is provided as shown in FIG. 7, the
width f at the upper end and the width g at the lower part
need not be a fixed width. Therefore, the degree of freedom
in designing increases, and also the strength can be
increased.
FIGS. 10 to 13 show the hook 6 of the side frame 2b.
As shown in FIG. 10, by forming the hook 6 integrally, the
hook 6 can be used as a hook for an S spring 14. When the
seat back frame is used for a single reclining seat, the need
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for a conventional retainer, which is installed subsequently,
is eliminated. The hook 6 is fixed by further crimping in
the arrow-marked direction from the state shown in FIG. 10.
Also, as shown in FIG. 11, by forming the attaching
piece 6a slightly larger for the S spring, a thick full mold
wire 15 can be attached in the same frame at a portion where
a weld 16 portion does not affect the frame strength.
Besides, as shown in FIG. 12, a mat 17 can also be attached
by crimping the attaching piece 6a. Also, since the
attaching piece 6a is formed with the retaining hole 6b, a
coil spring 18 for mat can be attached.
As shown in FIG. 14, when a passenger sits on a rear
seat on a two-door car, he/she enters the cabin through an
entrance 20 at the side of a front seat 19 by tilting a seat
back 21 forward.
In this embodiment, as shown in FIG. l, the side frames
2a and 2b are arranged so that the front side 12a is wider
and the rear side 12b is narrower than the reclining device
installation plane 12 of the seat back frame 1. Therefore,
as shown in FIG. 15, a corner portion 21a indicated by a
broken line at the rear side portion of the seat back 21 is
eliminated, so that the passenger can get on and off the car
easily.
Also, if the side frame planes of the automotive seat
back frame are in parallel in the longitudinal direction of
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the vehicle body and the seat width is narrow, the
passenger's body comes close to the front side of the side
frame, so that the passenger has a feeling of physical
disorder. Since the side frames 2a and 2b are arranged so as
to be wider in front as shown in FIG. 15, the shape of seat
back urethane mounted to the side frames 2a and 2b is fitted
to this form, providing a shape along the back of human body.
When the passenger sits on the seat, the seat back urethane
fits to the human body, by which the riding quality can be
upgraded.
Since as shown in FIG. 2, the seat back frame 1 is
curved by curving the line of AB-BC on the rear side of the
side frame 2a, 2b, the leg room for the passenger sitting on
the rear seat can be enlarged. The curved shape of the seat
back frame 1 serves as if a side support wire is attached
even if a side support wire is not disposed in the seat back
21.
As shown in FIG. 5, the step portion 7b is provided on
the installation plane 12 of the side frame 2a, 2b, and
welding is done so that the welding portion of the lower pipe
4 and the side frame 2a, 2b is drawn in. Thereby, the plane
rigidity around the welding portion 4a of the lower pipe 4 is
increased, and the crushing of the lower pipe 4 when a load
is applied is relaxed.
The above is a description of one embodiment of the
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present invention. Needless to say, the present invention is
not limited to this embodiment, and various modifications can
be made on the basis of the technical concept of the present
invention.
As described above, according to the first aspect of
the present inventions the same seat back frame can be used
for both of single reclining and double reclining.
Therefore, the same seat back frame can be produced in large
quantities, resulting in a decrease in production cost.
Also, according to the second aspect of the present
invention, since the bent portion is formed on the triangular
plane, the bent portion and tilting direction of the side
frame can be restricted when a backward load is applied to
the seat back frame. Also, the range of time for which the
load input can be controlled is widened, a heavy load can be
received for a long time, and no sudden moment change occurs
during deformation.
Further, according to the third aspect of the present
invention, both the effects of the first and second means can
be achieved. '
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