Patent Publication Number: US-2022219583-A1

Title: Vehicle seat

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application is a U.S. National Phase entry of, and claims priority to, PCT Application PCT/JP2020/022297, filed Jun. 5, 2020, which claims priority to Japanese Patent Application No. 2019-112543, filed Jun. 18, 2019, both of which are incorporated herein by reference in their entireties for all purposes. 
    
    
     BACKGROUND 
     The present invention relates to vehicle seats. 
     A vehicle seat is typically equipped with a seat frame within a seat cushion and within a seatback. The seat frame may include, for example, side frames arranged laterally spaced apart. Wires extend substantially in parallel to the side frames and between the side frames. A pad as a cushion material is placed on the side frames and the wires. The pad is covered with a cover made of an upholstery material. One example of this type of a vehicle seat is disclosed in JP2014-43160A. 
     A force in a left-right direction is applied to a seat pad from a seated person. This is especially the case as an acceleration force is applied in a left-right direction while a vehicle is turning. However, in a technology disclosed in JP2014-43160A, a back side of the pad (a side opposite to a seating surface) is not supported between the side frames and wires. As a result, deformation due to deflection of the pad may increase when the vehicle is turning. At such a time, the body of the seated person may not be sufficiently supported by the pad. A panel-type seat frame that is capable of supporting a pad entirely from a back side in order to avoid this insufficiency in support is known. However, there has been a problem in that this structure may lead to an increase in weight of the seat frame. 
     Therefore, there has been a need for a vehicle seat that can both effectively support a seated person when acceleration in the left-right direction is applied to the seated person and appropriately prevent any increase in weight. 
     BRIEF SUMMARY 
     According to one aspect of the present disclosure, a vehicle seat includes a seat cushion and/or a seatback. The seat cushion and/or seatback includes a seat frame and a pad body as a cushion material that is placed on the seat frame. The seat frame includes left and right side frames arranged spaced apart in the left-right direction. The seat frame also includes a wire or wires laid between the left and right side frames, with at least a part thereof extending substantially in parallel to the side frames. The pad body includes a first pad layer on a side of a seating surface and a second pad layer disposed on a side opposite to the seating surface of the first pad layer. The second pad layer is harder than the first pad layer. The second pad layer is supported while being in contact with the side frames and the wire or wires. 
     Both the side frames and the wire or wires support the pad body. Therefore, an increase in the weight of the seat frame can be suppressed more than that of a panel-type seat frame, which tends to be greater in weight. If acceleration in the left-right direction is applied to a vehicle seat and of a force is applied from a body of a seated person to the pad body, this force is received by the harder second pad layer. As a result, the pad body can support the body of the seated person well by suppressing the deformation due to deflection of the pad body. 
     According to another aspect of the present disclosure, the second pad layer includes a groove into which a wire is retained. The groove has a bottom that contacts the wire, and right and left walls that limit the relative movement of the wire in the left-right direction. A force may be applied from the body of the seated person to the pad body due to acceleration in the left-right direction of the vehicle. In this case, the wires and the right and left walls of the grooves restrict the second pad layer from moving in a left-right direction with respect to the wire. As a result, the pad body is prevented from moving in the left-right direction. 
     According to another aspect of the present disclosure, one or more projection configured to project from at least one of the left and right walls is provided to prevent the wire inserted in the groove from coming out of the groove. Therefore, it is possible to prevent the wire from coming out the groove with a simple structure. 
     According to another aspect of the present disclosure, the first pad layer is a polyurethane resin foam. The second pad layer is a polyolefin resin bead foam. Therefore, the first pad layer can maintain the seating comfort of the vehicle seat. The second pad layer can maintain the support rigidity of the pad body. As a result, the pad body may exhibit a well-balanced performance while suppressing an increase in weight. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a vehicle seat according to one embodiment of the present invention. 
         FIG. 2  is an exploded perspective view of a seatback of the vehicle seat according to said embodiment. 
         FIG. 3  is a cross-sectional view taken along a line of  FIG. 1 . 
         FIG. 4  is a cross-sectional view taken along a line IV-IV of  FIG. 1 . 
         FIG. 5  is a cross-sectional view taken along a line V-V of  FIG. 1 . 
         FIG. 6  is a cross-sectional view taken along a line VI-VI of  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION 
     One embodiment of the present disclosure will be described with reference to  FIGS. 1 to 6 . The present embodiment relates to, for example, a vehicle seat  1  as one example of various vehicle seats. Arrows in each drawing indicate each direction of a vehicle and the vehicle seat  1  when the vehicle seat  1  is mounted on a floor F of the vehicle. In the following description, directions will be described on the basis of these directions. A left-right direction of this embodiment is a vehicle width direction. 
     As shown in  FIG. 1 , the vehicle seat  1  according to the present embodiment includes a seat cushion  2  and a seatback  3 . A lower end of the seatback  3  is attached to a rear end of the seat cushion  2 , for instance via a recliner  4  (see  FIG. 2 ). A reclined angle of the seatback  3  can be adjusted with respect to the seat cushion  2 . Since the seat cushion  2  is of a known structure, the description thereof will be omitted. An embodiment of the seatback  3  will be described, features of which may also be extended to a seat cushion. 
     As shown in  FIG. 2  to  FIG. 5 , the seatback  3  includes a back frame (seat frame)  10  as a skeleton, a back pad (pad body)  20  as a cushion material, and a back cover  30  as an upholstery material. 
     As shown in  FIG. 2  to  FIG. 5 , the back frame  10  is configured to have a rectangular frame following substantially along an outer peripheral shape of the seatback  3  from a front view. More specifically, the back frame  10  includes a left side frame  11 , a right side frame  11 , an upper panel  12 , and a lower panel  13 . The side frames  11  may be, for example, made of a steel plate and are long in an up-down direction. The upper panel  12  may be, for example, made of a steel plate and laid between upper ends of the side frames  11 . The lower panel  13  may be, for example, made of a steel plate and laid between lower ends of the side frames  11 . Left and right wires  14  may be laid between the upper panel  12  and the lower panel  13 . The wires  14  may extends in substantially an up-down direction. A headrest frame  15  is attached to the upper panel  12 . 
     As shown in  FIG. 3  to  FIG. 5 , each of the side frames  11  includes a front edge and a rear edge having a shape that is bent inward in a left-right direction (inward in a seat width direction). This shape enhances the stiffness of the side frames  11  against bending or twisting. More specifically, each of the side frames  11  includes a side wall  11   a  facing the other side frame. The side walls  11   a  may extend in the up/down direction. A front wall  11   b  extends from the front end of the side wall  11   a  and extends inward in the left-right direction. A rear wall  11   c  extends from a rear end of the side wall  11   a  and extends inward in the left-right direction. The rear wall  11   c  is longer in the left-right direction than the front wall  11   b.    
     As shown in  FIG. 2  to  FIG. 5 , each of the wires  14  includes an upper sloped part  14   a  that gradually inclines downward from above and toward the inside in the left-right direction. A vertical part  14   b  extends downward from a lower end of the upper sloped part  14   a . A lower sloped part  14   c  gradually inclines downward from a lower end of the vertical part  14   b  and toward the outside the vertical part  14   b  in the left-right direction. The vertical parts  14   b  of the wires  14  extend in parallel in the up-down direction, as viewed from the front. An upper end of each upper sloped part  14   a  is attached to the upper panel  12 . A lower end of each lower sloped part  14   c  is connected to a connecting part  14   d . The connecting part  14   d  extends in the left-right direction. The connecting part  14   d  is attached to the lower panel  13 . An airbag  5  is retained in the right side of the right side frame  11 . 
     As shown in  FIG. 2  to  FIG. 5 , the back pad  20  includes a first pad layer  21  and a second pad layer  22 . The first pad layer  21  may be, for example, a polyurethane resin foam (urethane foam). The density of the first pad layer  21  may be, for example, about 0.045±0.005 g/cm 3 . The second pad layer  22  has a higher elastic modulus and is harder than the first pad layer  21 . The second pad layer  22  may be, for example, an olefin resin bead foam, such as polypropylene or polyethylene. The density of the second pad layer  22  is lower than that of the first pad layer  21 , and may be, for example, about 0.03 g/cm 3 . The first pad layer  21  and the second pad layer  22  are integrally formed during molding. Alternatively, they may be integrally formed by attaching together. 
     As shown in  FIG. 2  to  FIG. 5 , the first pad layer  21  includes a surface side  21   a , which is a surface on the side of the seating surface of the back pad  20 . The first pad layer  21  also includes a back side  21   b , which is a surface on a side of the first pad layer  21  opposite to the seating surface. The first pad layer  21  includes a main part  21 A, inner side parts  21 B located on the left and right of the main part  21 A, and outer side parts  21 C located outside the inner side parts  21 B in the left-right direction. The main part  21 A supports the waist or back of the seated person P from behind. The inner side parts  21 B extends from the left and right ends of the main part  21 A and support the sides of the waist or back of the seated person P. The outer side parts  21 C extend from the left and right outer ends of the inner side parts  21 B. The outer side parts  21 C extend along the inner side parts  21 B so as to cover the outer sides of the side frames  11  in the left-right direction. The rear ends of the outer side parts  21 C extend along a rear surface of the rear walls  11   c  of the side frames  11 . The rear ends of the outer side parts  21 C cover the rear walls  11   c  from behind. 
     As shown in  FIG. 2  to  FIG. 5 , grooves  21   c  are defined at the border between the main part  21 A and the inner side parts  21 B. A cross-section of the groove  21   c  opens forward and extends in an up-down direction. A wall surface of the groove  21   c  is substantially U-shaped in a cross-section. Locked members (not shown) are inserted into a bottom part, which is opposite to an opening, of the groove  21   c . The back cover  30  includes a surface (rear surface) opposite to the seating surface and locking members are attached at predetermined positions on the rear surface. The locking members are locked to the locked members such that the back cover  30  is fixed to the back pad  20 . 
     As shown in  FIG. 2  to  FIG. 5 , the second pad layer  22  includes a surface side  22   a  and back side  22   b . The surface side  22   a  comes in contact with back side  21   b  of the first pad layer  21  at the main part  21 A and at the inner side parts  21 B. The back side  22   b  of the second pad layer  22  may form a surface opposite to the seating surface of the back pad  20 . The second pad layer  22  includes a main part  22 A and side parts  22 B formed along left and right edges of the main part  22 A. The main part  22 A is located on the back side of the main part  21 A of the first pad layer  21 . The side parts  22 B of the second pad layer  22  are located on the back side of the inner side parts  21 B of the first pad layer  21 . 
     As shown in  FIG. 2  to  FIG. 5 , the surface side  22   a  of the main part  22 A of the second pad layer  22  is adhered to the back side  21   b  of the main part  21 A of the first pad layer  21 . This allows the main part  22 A of the second pad layer  22  to be connected to the main part  21 A of the first pad layer  21 . Grooves  22   b   1 , into which respective wires  14  are installed, are provided on the back side  22   b  of the main part  22 A of the second pad layer  22 . Each of the grooves  22   b   1  has a cross-section corresponding to each wire  14 , opens rearward, and may have, for example, a substantially right-angled shape. Specifically, each groove  22   b   1  includes an inner wall (right wall or left wall) located toward the center of the seatback  3  in the left-right direction, and an outer wall (left wall or right wall) located outside the inner wall in the left-right direction. The inner wall extends forward from and substantially orthogonal to the back side  22   b . The outer wall is inclined relative to the back side  22   b  of the second pad layer  22 . The outer wall extends forward from the back side  22   b  and toward the center of the seatback  3  in the left-right direction. Bottoms  22   b   11  of the grooves  22   b   1  are defined at locations where the inner wall and the outer wall intersect. When the back pad  20  is placed on the back frame  10 , each wire  14  comes in contact with the bottom  11   b   11  of corresponding grooves  22   b   1 . 
     As shown in  FIG. 2  and  FIG. 3 , projections  22   b   12  are formed on the wall surfaces of the grooves  22   b   1 . The projections  22   b   12  are configured to prevent the wires  14  from being pulled out of the grooves  22   b   1 . Each of the projections  22   b   12  may, for example, project outward from the inner wall of the groove  22   b   1  in the left-right direction, so as to be located behind the wire  14 . The projections  22   b   12  are located at positions corresponding to upper parts of the wires  14 . For example, the projections  22   b   12  may be located at positions corresponding to the upper parts of the vertical parts  14   b  and to the upper sloped parts  14   a  of the wires  14 . When the wires  14  are inserted into the grooves  22   b   1 , the projections  22   b   12  interfere with the wires  14  such that the projections  22   b   12  are compressed and deformed in the left-right direction. The wires  14  extend beyond the projections  22   b   12  and come in contact with the bottoms  22   b   11  of the grooves  22   b   1 , such that the deformation of the projections  22   b   12  is elastically restored. When the force in the front-rear direction is exerted on the back pad  20 , the projections  22   b   12  help prevent the wires  14  from coming out of the grooves  22   b   1 . 
     As shown in  FIG. 2  to  FIG. 5 , the surface side  22   a  of the side parts  22 B of the second pad layer  22  is adhered to the back side  21   b  of the inner side parts  21 B of the first pad layer  21 . This allows the side parts  22 B of the second pad layer  22  and the inner side parts  21 B of the first pad layer  21  to be connected with each other. The back sides  22   b  on left and right ends of the side parts  22 B of the second pad layer  22  are provided with locking parts  22   b   2  outwardly extending in the left and right directions. Each of the locking parts  22   b   2  comes in contact with the front side of each front wall part  11   b  of the side frame  11  when the back pad  20  is placed on the back frame  10 . 
     The back pad  20  shown in  FIG. 3  may have a first pad layer  21  and a second pad layer  22  that are integrally formed during molding. For example, the second pad layer  22 , which may have been bead foam molded in advance, may be placed in a mold having a cavity formed in a shape of the back pad  20 . A foam material made of polyurethane resin may be injected into the mold to foam-mold the first pad layer  21 . 
     As shown in  FIG. 2  to  FIG. 5 , the back cover  30  has a plurality of parts that are sewn together. The back cover  30  has a bag shape with an open back. The back cover  30  covers the back pad  20 , which is placed on the back frame  10 , such that the surface shape of the back cover  30  generally follows the outer shape of the seatback  3 . 
     The present embodiment as configured above may provide the following effects. As shown in  FIG. 2 , the back pad  20  includes a first pad layer  21  and a second pad layer  22 . The second pad layer  22  is harder than the first pad layer  21 . The first pad layer  21  and the second pad layer  22  are laminated. The second pad layer  22  contacts the side frames  11  and the wires  14  so as to be supported. This enables the back frame to be more lightweight than a panel-type back frame. A panel-type back frame is more likely to be greater in weight. When a force, for example due to acceleration, in the left-right direction is applied to the vehicle seat  1 , the force is applied from the body of the seated person P to the back pad  20 . The second pad layer  22  receives the force and suppresses the deformation due to deflection of the back pad  20 , such that the body of the seated person P may be well supported by the second pad layer  22 . 
     As shown in  FIG. 2 , the second pad layer  22  is supported by the wires  14 , which are in contact with the bottoms  22   b   11  of the grooves  22   b   1 . The forces, for instance due to acceleration, in the left-right direction are applied to the vehicle seat  1  and the forces in the left-right direction are applied from the body of the seated person P to the back pad  20 . At this time, the left and right walls of the groove  22   b   1  come in contact with the wire  14 , such that the wires  14  prevent the second pad layer  22  from moving in the left-right direction. This structure is a relatively simple structure. 
     As shown in  FIG. 2 , a projection  22   b   12  is provided on at least one of the left and right walls of the groove  22   b   1 . The projection  22   b   12  prevents the wire  14 , which is inserted into the groove  22   b   1 , from coming out of the groove  22   b   1 . Therefore, it is possible to prevent the wires from coming out of the grooves  22   b   1  with a simple structure. For example, the wires  14  may be prevented from coming out of the grooves  22   b   1  when a force in the left-right direction is applied to the back pad  20  from the body of the seated person P when the force due to acceleration in the left-right direction is applied to the vehicle seat  1 . 
     The first pad layer  21  shown in  FIG. 2 , etc. is a polyurethane resin foam. This allows the first pad layer  21  to maintain the seating comfort of the vehicle seat  1 . The second pad layer  22  is a polyolefin resin bead foam. This allows the second pad layer  22  to maintain the support rigidity of the back pad  20 . As a result, the back pad  20  may exhibit a well-balanced performance while suppressing an increase in weight. 
     Although specific embodiments have been described above, the features of the present disclosure shall not be limited to their appearance and configuration, and various changes, additions, and deletions are possible to the extent that they do not change the gist of the present disclosure. For example, the following may be implemented. 
     The technology applied to the seatback  3  in the above embodiments may also be applied to the seat cushion  2 . The technology applied to the vehicle seat  1  in the above embodiments may also be applied to seats mounted in airplanes, ships, trains, etc. 
     The side frames  11  in the above embodiments may be made of a steel plate material. The side frames  11  may have a side wall  11   a , a front wall  11   b , and rear walls  11   c . Alternatively, the side frame may be a frame in a form of a pipe. Alternatively the side frames may have wire members or plate-like members, which come in contact with the locking parts  22   b   2  of the second pad layer  22  to support the second pad layer  22 .