Title of Invention

CENTER HINGE STRUCTURE FOR SPLIT-FOLDING TYPE SEAT BACK

Abstract A center hinge (3) for split-folding type seat backs (11,12) includes a fixed hinge member (30) fixed to the vehicle body side and a pair of left and right movable hinge members (31, 32) for fixing the left and right seat backs (11,12). The fixed hinge member (30) includes a base (30b) serving as a fixing surface to the vehicle body side and a support (30a) erected fi"om one side of the base perpendicularly to the axis in the vehicle width direction via a bent part (3 Of), and the movable hinge members are pivotally supported on the support. In the bent part, a reinforcing bead (34) is formed at a position at which the base intersects with a straight line (K) connecting a turning center (33 a) of the movable hinge member to the center of a bolt hole (30c), as viewed fi'om the side.
Full Text

CENTER HINGE STRUCTURE FOR SPLIT-FOLDING TYPE SEAT BACK
Field of the Invention The present invention relates to a center hinge structure for a split-folding type seat back that is arranged in front of a cargo compartment and can be folded forward by being split to the right and left.
Backgroimd of the Invention Conventionally, a vehicle having an interior construction in which a cargo compartment is arranged in the rear part, such as a station wagon, passenger car, and van, has been configured so that a seat back of a rear seat located in front of the cargo compartment is folded and lapped on a seat cushion to make the back surface of the seat back continuous with the floor surface of the cargo compartment, by which the space of the rear seat is utilized as a part of cargo compartment space. In this case, for the station wagon or passenger car, a split-folding type seat back is generally used, in which the cargo compartment space can be expanded while a seat for one or two persons is secured on the rear seat by splitting the seat back to the right and left in a proportion of 5 to 5 or 6 to 4 and hence making the split seat backs capable of being folded forward independently.
For the above-described split-folding type seat back, hinges (71, 72, 73 in Fig. 6) for tumably supporting the left and right seat backs (61, 62) are provided at the left and right sides and in a central split part of the rear seat, and in the state in which the seat backs are erected so that the passengers can be seated, lock mechanisms provided near the upper ends on the left and right sides of the seat back are locked by being engaged with strikers (74, 75). However, for such a split-folding type seat back, as shown in Fig. 6, the left and right seat backs 61 and 62 are independent, and no support mechanism is present in an upper part of

the intermediate part of the seat backs. Therefore, in the case where a shock load acts from the vehicle front during the running of vehicle, if the shock of a cargo 60 moving forward is given to the seat backs 61 and 62, the left and right seat backs 61 and 62 become split apart, and hence the center hinge 73 may be damaged.
To solve this problem, there has been developed a technique for providing a connection mechanism on the left and right seat backs 61 and 62, or a technique in which engagement mechanisms that engage with each other when the left and right seat backs are displaced in the separating direction are provided in the left and right movable hinge parts of the center hinge 73 (refer to JP 8-216750 A and JP 11-208336 A). However, in the foraier technique, since the connection mechanism and the left and right lock mechanisms are interlocked, even when either one of the seat backs is folded, unlock knobs on both left and right sides must be operated at the same time, which offers a drawback to operability. Also, in the latter technique, since the engagement mechanisms are provided near the center hinge (73), it is difficult to attain a sufficient locking force, and also it is possible that convex and concave portions are not engaged with each other depending on the deforaiation mode of seat backs. Therefore, such a structure fails to provide advantageous effects that are commensurate with the increase in complexity and manufacturing costs.
Brief Summary of the Invention The present invention has been made in view of the above circumstances, and accordingly an object thereof is to provide a center hinge structure for a split-folding type seat back, capable of preventing damage or deformation to the seat back when a shock load is applied and the bouncing-out of a cargo to the passenger seat side caused by damage or deformation to the seat back by increasing the strength of a center hinge and hence preventing the deformation of the hinge itself without adding other mechanisms or members.

To solve the problems that the above-described related art has, the present invention provides a center hinge structure for a split-folding type seat back which is arranged in front of a cargo compartment and is supported tumably by side hinges disposed on the left and right sides with the center hinge disposed in a central split part, so as to be able to fold by being split to the right and left, the center hinge comprising a fixed hinge member fixed to the vehicle body side and a pair of movable hinge members fixed to the right and left seat backs, the fixed hinge member having a base portion provided with a fixing surface to the vehicle body side and a support portion erected from one side of the base portion perpendicularly to the axis in the vehicle width direction via a bent part, and the movable hinge members being pivotally supported at the upper end of the support portion, and the base portion being formed with a bolt hole which can be inserted a bolt for threadedly fixing the fixed hinge member,
wherein a reinforcing bead is formed in the bent part at a position at which the base portion intersects with a line connecting a turning center of the movable hinge member to the center of the bolt hole in the fixed hinge member in side view.
Since the present invention has the above-described feature, the strength of the fixed hinge member constituting the center hinge, especially, the rigidity in the bent part between the base and the support is enhanced, and damage or deformation to the seat back at the time when a shock load is applied and the bouncing-out of a cargo to the passenger seat side caused by damage or deformation to the seat back can be prevented. Moreover, since the reinforcing bead is formed only by plastic working for expanding the bent part of the fixed hinge member, the addition of other members is not involved, and the parts are not increased in size. Therefore, the center hinge structure is favorable when being installed in a narrow gap in the seat back split part.
Also, in a preferred mode of the present invention, the reinforcing bead is formed as

a triangular bead having a ridgeline directed crosswise to the bent part and extending slantwise between the support and the base, and being disposed so that the ridgeline is offset from the center of the bolt hole toward the vehicle rear. Therefore, on the base, interference in the vehicle width direction between the reinforcing bead and the head of bolt is prevented, and the base formed with the bolt hole can be made compact Also, the bolt can be arranged close to the bent part and the reinforcing bead. Therefore, the center hinge structure is advantageous in increasing the joint strength of the fixed hinge member.
Further, in a mode in which the base is formed with one or a plurality of other bolt holes in addition to the above-described bolt hole; the bolt hole and the other bolt hole are disposed so as to be arranged in the front and rear direction of vehicle; and the bolt hole has a hole diameter suitable for the diameter of a bolt inserted through the bolt hole, and the other bolt hole has a diameter larger than the hole diameter suitable for the diameter of a bolt inserted through the hole or is an elongated hole, when the fixed hinge member is mounted, an error of mounting position of the vehicle body side bolt hole with respect to the bolt hole is absorbed, and hence high moimting properties are secured. In the case where a shock load is applied to the seat backs from the rear, a shift corresponding to the absorption of the error is difficult to occur on the fixed hinge member because the dimensional accuracy of bolt hole to which the shock load is transmitted directly from the center hinge through the reinforcing bead is high. Therefore, the fixed hinge member is firmly integrated with the vehicle body side, the load can be received distributedly by the vehicle body side, and the deformation and damage of the center hinge can be restrained.
Also, in a mode in which a moimting surface on the vehicle body side, to which the base of the fixed hinge member is fixed, is an inclined surface that is higher toward the vehicle rear, since the joint part between the base and the vehicle body side moxmting surface is arranged slantwise, the rigidity of the fixed hinge member against the bending in

the vehicle width direction is improved, and the distance from the base to the turning axis on the vehicle rear side of the fixed hinge member is shortened. Thereby, the strength of the fixed hinge member against the bending in the front and rear direction of vehicle is also improved, and the joint length of the joint part is increased. Therefore, the joint strength is enhanced, and fiirther when the above-described shock load is applied from the rear, loads not only in the shear direction but also in the pnllout direction are applied to the bolt, so that the fixing strength of the fixed hinge member is improved. Along with the configuration in which the reinforcing bead is provided, the deformation and damage of the center hinge can be restrained effectively.
Brief Description of the Several Views of the Drawing Fig. 1 is a perspective view of a vehicular seat provided with split-folding type seat
backs in accordance with an embodiment of the present invention, being viewed from the
rear;
Fig. 2 is a partially cutaway side view of the vehicular seat shown in Fig. 1;
Fig. 3 is a side sectional view of an essential portion, showing the vicinity of a center
hinge of the split-folding type seat backs shown in Fig. 1;
Fig. 4 is a front view of the center hinge shown in Fig. 3;
Fig. 5 is a perspective view of the center hinge shown in Fig. 3; and
Fig. 6 is a schematic plan view showing a state in which a load acts on split-folding
type seat backs from the rear.
Detailed Description of the Invention An embodiment of the present invention will now be described in detail with reference to the accompanying drawings. Fig. 1 is a perspective view of a vehicular rear

seat 1 provided with split-folding type seat backs 11 and 12 in which the present invention is embodied, being viewed from the rear (the cargo compartment side of vehicle). In Fig. 1, the rear seat 1 has a seat cushion 13 for passengers to be seated, and the seat backs 11 and 12 are erected upward from the rear end of the seat cushion 13. The left and right seat backs 11 and 12 are pivotally supported by side hinges 21 and 22 disposed at the lower ends on the left and right sides and a center hinge 3 disposed at the lower end of the split part so that the seat backs 11 and 12 can be folded forward and pulled up independently.
In the upper parts on the left and right side faces of the seat backs 11 and 12, lock mechanisms 41 and 42 are provided additionally. By engaging the lock mechanism 41, 42 with a striker (not shown) fixed to the side body, the seat back 11,12 can be held in an erected state. On the other hand, by operating an unlock knob 41a, 42a, the lock mechanism 41,42 can be unlocked so that the seat back 11, 12 can be folded forward.
The side hinges 21 and 22 are fixed directly to a floor panel 5, and the center hinge 3 is fixed to a vehicle body floor 5 via a hinge bracket 2. As shown in Figs. 1 and 3, the hinge bracket 2 is pressed into a trapezoidal shape having side walls 2b on both sides of an upper surface 2a, and the lower ends of the side walls 2b are fixed to the floor panel 5 by using fastening members such as bolts. The hinge bracket 2 may be formed integrally with the floor panel 5.
Fig. 2 is a side view showing the positional relationship between the rear seat 1 and a cargo compartment 6. A passenger room and the cargo compartment are defined in the front and rear direction of the vehicle by the seat backs 11 and 12 of the rear seat 1. On both of the left and right sides of the cargo compartment 6, tire houses 51 are expanded, and in a recess in the middle portion therebetween, a spare tire storing space 50 is formed. The tire houses 51 and the spare tire storing space 50 are formed by the floor panel 5 continuous with a floor surface on which the seat cushion 13 is mounted. A luggage board 61 is

mounted so as to secure a flat cargo compartment floor surface above the storing space 50 ranging to the left and right tire houses 51, and a cargo 60 can be placed thereon.
In the upper surface 2a of the hinge bracket 2, serving as a fixing surface, two bolt holes 2c and 2d arranged in the fi"ont and rear direction of vehicle are fonBed. In the example shown in the figures, weld nuts 2e and 2f are welded on the back surface side of the upper surface 2a. Also, the upper surface 2a of the hinge bracket 2 forms an inclined siirface that is higher toward the vehicle rear for the later-described reason, so that when the center hinge 3 is fixed to the hinge bracket 2, a base 30b of the center hinge 3 is fixed in a state of being inclined toward the vehicle fi'ont.
The center hinge 3 includes a fixed hinge member 30 for fixing the center hinge 3 on the floor side of vehicle body (the hinge bracket 2) and a pair of movable hinge members 31 and 32 fixed to the seat backs 11 and 12 on the left and right sides, respectively.
As shown in Figs. 4 and 5, the movable hinge member 31, 32 includes a turning surface 31a, 32a and a seat back fixing surface 31b, 32b that is bent at right angles fi'om the turning surface 31a, 32a and extends to the side, and has a substantially L-shaped cross section. The movable hinge members 31 and 32 are arranged in a lapped manner on both sides of a support 30a of the fixed hinge member 30. A pin 33 (the turning axis) is caused to penetrate through the movable hinge members 31 and 32 and the support 30a, and the end parts of the pin 33 are prevented fi"om coming off by caulking etc., by which the movable hinge members 31 and 32 are supported on the fixed hinge member 30 so as to be tumable independently. The seat back fixing surface 3 lb, 32b is fonned with a bolt hole 31c, 32c. A bolt (not shown) inserted through the bolt hole 31c, 32c is engaged threadedly with a weld nut (not shown) on the inside of the back surface of the seat back 11, 12, by which the seat back fixing surface 3 lb, 32b is fixed to the seat back 11, 12.
The fixed hinge member 30 is formed by bending a plate-shaped material such as a

metal plate. The fixed hinge member 30 includes the base 30b forming a fixing surface to the hinge bracket 2 and the support 30a connected to the base 30b via a bent part 3 Of and erected perpendicularly to the axis in the vehicle width direction, and is formed so as to have a substantially L-shaped cross section. The support 30b is formed so as to extend fi"om the rear side of the base 30b and be curved to the fi-ont on the upper end side so that the turning axes of the seat backs 11 and 12 are disposed above the rear end of the seat cushion 13 avoiding the rear end thereof On the other hand, the base 30b is formed with two bolt holes 30c and 30d. These bolt holes 30c and 30d are aligned with the bolt holes 2c and 2d in the hinge bracket 2, and bolts 35c and 35d are inserted fi-om the upside and engaged threadedly with the weld nuts 2e and 2f, by which the fixed hinge member 30 is fixed to the hinge bracket 2.
In the bent part 30f of the fixed hinge member 30, a reinforcing bead 34 is provided at a position at which the base 30b intersects with a straight line connecting a turning center 33a of the movable hinge members 31 and 32 to the center of the bolt hole 30c, as viewed fi'om the side (Fig. 3). As shown in Figs. 4 and 5, the reinforcing bead 34 expands to the inside of the bent part 30f, that is, to the side on which two surfaces of the support 30a and the base 30b face to each other, is disposed in the direction such as to intersect with the bent part 30f, and has a ridgeline 34a extending slantwise between the support 30a and the base 30b. The reinforcing bead 34 typically shown in the figures is a triangular bead in which the cross section perpendicular to the ridgeline 34a takes a triangular shape. However, the cross-sectional shape of the reinforcing bead 34 is not limited to a triangular shape, and can be a trapezoidal shape, an arcuate shape, or the like. Nevertheless, the triangular bead is suitable because the ridgeline 34a can be made high as compared with the moimting area and because the bead 34 can be disposed close to the bolt 35c inserted through the bolt hole 30c while avoiding the interference with the bolt 35c.

Relating to the above description, the reinforcing bead 34 is arranged so that the ridgeline 34a shifts to the rear in the front and rear direction of vehicle from the center of bolt hole 30c. Thereby, the ridgeline 34a projecting in the vehicle width direction farthest from the bent part 30f can be separated from the bolt 35c. Therefore, the reinforcing bead 34 and the bolt 35c are brought close to each other while avoiding the interference between the reinforcing bead 34 and the head of the bolt 35c, and the bolt 35c is arranged close to the bent part 30f, by which the joint strength of the fixed hinge member 30 is increased. Also, the base 30b of the fixed hinge member 30 can be made compact. In the embodiment shown in the figures, the turning axis (the pin 33) of the movable hinge members 31 and 32, the bolt hole 30c in the fixed hinge member 30, and the reinforcing bead 34 are arranged in a straight line in the up and down direction (the vertical direction of vehicle) as viewed from the side.
Further, in this embodiment, the bolt holes 30c and 30d are provided at two locations in the front and rear direction of vehicle. In the case where a plurality of bolt holes are arranged in this manner, variations in dimensional accuracy with respect to the bolt holes 2c and 2d in the hinge bracket 2 (or the floor panel 5), which is a mounting part, must be considered. It is advantageous in terms of workability at the mounting time to fix the weld nuts 2e and 2f in advance to the hinge bracket 2 (or the floor panel 5), which is a part on the vehicle body side. Therefore, it is necessary to absorb the above-described variations in dimensional accuracy on side of the center hinge 3 moimted to the hinge bracket 2 (or the floor panel 5) to prevent poor assembling.
Thereupon, of the plurality of bolt holes 30c and 30d, the bolt hole 30c located at the rear in the front and rear direction of vehicle is made a dimension reference hole having a diameter corresponding to the diameter of the tightening bolt 35c used, and the other bolt hole 30d is made a large-diameter hole or an elongated hole as compared with the diameter

of the tightening bolt 35d. Thereby, the variations in dimensional accuracy can be absorbed, and also a positional shift of the bolt hole 30c on the rear side in the case where a load is applied to the center hinge 3 from the rear side of vehicle and the turning of the center hinge in the joint plane caused by the positional shift of the bolt hole 30c are prevented, the bending strength of the fixed hinge member 30 disposed in the front and rear direction of vehicle is held to the maximum, and the deformation and damage of the center hinge 3 are prevented
When the vehicle provided with the above-described center hinge structure runs, if a shock load is applied to the vehicle from the front, the cargo 60 placed in the cargo compartment 6 moves toward the vehicle front and collides with the seat backs 11 and 12 as shown in Fig. 2. At this time, a force that tends to deform the seat backs 11 and 12 so that the central split part opens to the outside acts on the seat backs 11 and 12 because the lower parts of the seat backs 11 and 12 are supported by the side hinges 21 and 22 and the center hinge 3, and the upper parts thereof on the left and right sides are supported by the lock mechanisms 41 and 42, whereas no connecting structure is present in the upper part of the central split part.
Therefore, a load that pulls the movable hinge members 31 and 32 to the front and to the left and right and is directed slantwise upward acts on the center hinge 3 of the seat backs 11 and 12, so that the bent part 30f tends to deform in the opened direction. However, since the reinforcing bead 34 is provided in the bent part 30f, the bending rigidity and torsional rigidity of the bent part 30f are enhanced, so that the deformation of the bent part 30f is restrained, and thereby the deformation and damage of the center hinge 3 are prevented. In particular, by the reinforcing bead 34 arranged close to the bolt 35c, the rigidity of the base 30b itself is enhanced, and deformation of the base 30b such as to get turned up from the joint surface (2a) is restrained. Since the base 30b is finnly integrated

with the joint surface, the deformation and damage of the center hinge 3 are prevented.
Specifically, since the turning center 33a (the pin 33) of the movable hinge members 31 and 32, the bolt hole 30c in the fixed hinge member 30, and the reinforcing bead 34 are arranged in a straight line in the up and down direction as viewed fi-om the side, the deformation of the fixed hinge member 30 and the positional shift fi-om the turning center 33a to the vehicle body of the mounting part caused by the deformation of the fixed hinge member 30 are restrained, and the fixed hinge member 30 is held in a mounting posture capable of attaining the highest strength. Therefore, the shock load is surely transmitted fi"om the movable hinge members 31 and 32 to the pin 33, the fixed hinge member 30, the bolt hole 30c, the hinge bracket 2, and the floor panel 5, so that the deformation and damage of the seat backs 11 and 12 and the center hinge 3 are prevented.
Further, since the upper surface 2a of the hinge bracket 2, to which the base 30b of the fixed hinge member 30 is fixed, is an inclined surface that is higher toward the vehicle rear, the bending rigidity of the fixed hinge member 30 is further enhanced, and not only a shearing stress but also an axial tensile stress acts on the bolts 35c and 35d that fix the center hinge 3, so that the axial tensile strength most advantageous in terms of strength to a fastening member such as a bolt can be utilized for the fixing structure of the center hinge 3. Therefore, this center hinge structure is advantageous.
In the above-described embodiment, the case where the two bolt holes 30c and 30d are provided in the base 30b, and the base 30b is fixed by the two bolts 35c and 35d has been shown. However, the bolt holes may be provided at three or more locations. Also, the configuration can be made such that the fi-ont bolt hole 30d is changed to a claw etc. engaging with the bolt hole 2d, and the base 30b is fijced by one rear bolt 35c only. Also, in the above-described embodiment, the case where the left and right seat backs 11 and 12 are split in a proportion of 5 to 5 has been shown. However, the present invention can be

applied to the case where the left and right seat backs are split in another proportion of, for example, 6 to 4.
The above is a description of one embodiment of the present invention. It is a matter of coxirse that the present invention is not limited to the above-described embodiment, and various modifications and changes can be made based on the technical concept of the present invention.










What is claimed is:
1. A center hinge structure for a split-folding type seat back which is arranged in front
of a cargo compartment and is supported tumably by side hinges disposed on the left and
right sides with the center hinge disposed in a central spht part, so as to be able to fold by
being spUt to the right and left, the center hinge comprising a fixed hinge member fixed to
the vehicle body side and a pair of movable hinge members fixed to the right and left seat
backs, the fixed hinge member having a base portion provided with a fixing surface to the
vehicle body side and a support portion erected from one side of the base portion
perpendicularly to the axis in the vehicle width direction via a bent part, and the movable
hinge members being pivotally supported at the upper end of the support portion, and the
base portion being formed with a bolt hole which can be inserted a bolt for threadedly
fixing the fixed hinge member,
wherein a reinforcing bead is formed in the bent part at a position at which the base portion intersects with a line connecting a turning center of the movable hinge member to the center of the bolt hole in the fixed hinge member in side view.
2. The center hinge structure according to claim 1, wherein the reinforcing bead is formed as a triangular bead having a ridgeline directed crosswise to the bent part and extending slantwise between the support and the base, and being disposed so that the ridgeline is offset from the center of the bolt hole toward the vehicle rear.
3. The center hinge structure according to claim 1, wherein the base portion is formed with one or a plurality of other bolt holes in addition to the bolt hole; the bolt hole and the other bolt hole are disposed so as to be arranged in the front and rear direction of the vehicle; the bolt hole has a hole diameter suitable for the diameter of a bolt inserted through the bolt hole, and the other bolt hole has a diameter larger than the hole diameter suitable for the diameter of a bolt inserted through the hole or is an elongated hole.

4. The center hinge structure according to any one of claims 1 to 3, wherein a mounting surface on the vehicle body side, to which the base of the fixed hinge member is fixed, is an inclined surface that is higher toward the vehicle rear.


Documents:

1386-CHE-2007 POWER OF ATTORNEY 28-09-2010.pdf

1386-CHE-2007 AMENDED CLAIMS 28-09-2010.pdf

1386-CHE-2007 EXAMINATION REPORT REPLY RECIEVED 28-09-2010.pdf

1386-che-2007 form-3 28-09-2010.pdf

1386-che-2007-abstract.pdf

1386-che-2007-claims.pdf

1386-che-2007-correspondnece-others.pdf

1386-che-2007-description(complete).pdf

1386-che-2007-drawings.pdf

1386-che-2007-form 1.pdf

1386-che-2007-form 18.pdf

1386-che-2007-form 3.pdf

1386-che-2007-form 5.pdf


Patent Number 244263
Indian Patent Application Number 1386/CHE/2007
PG Journal Number 49/2010
Publication Date 03-Dec-2010
Grant Date 26-Nov-2010
Date of Filing 27-Jun-2007
Name of Patentee SUZUKI MOTOR CORPORATION
Applicant Address 300, TAKATSUKA-CHO, MINAMI-KU, HAMAMATSU-SHI, SHIZUOKA-KEN, JAPAN.
Inventors:
# Inventor's Name Inventor's Address
1 HIRABARU, YASUNORI C/O SUZUKI MOTOR CORPORATION, 300, TAKATSUKA-CHO, MINAMI-KU, HAMAMATSU-SHI, SHIZUOKA-KEN, JAPAN.
PCT International Classification Number B60N 2/00
PCT International Application Number N/A
PCT International Filing date
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 2006-177699 2006-06-28 Japan