Vehicle seat

A vehicle seat includes: a seat pad; and an air bag placed on a back side of the seat pad and configured to be expandable. The seat pad includes a jump-out portion and an unfolding portion extending. When the air bag jumps out, the unfolding portion is pushed aside while deforming in a bending manner from a part serving as a base point at the time when the unfolding portion is pushed aside by the air bag. The unfolding portion includes a deformable portion that is easy to deform as compared with other parts of the unfolding portion, the deformable portion being placed at the part serving as the base point, and at the time when the air bag jumps out, the deformable portion deforms so as promote the unfolding portion to deform in a bending manner so that the unfolding portion is pushed aside toward the one side.

INCORPORATION BY REFERENCE

The disclosure of Japanese Patent Application No. 2014-226761 filed on Nov. 7, 2014 including the specification, drawings and abstract is incorporated herein by reference in its entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a vehicle seat including a seat pad for elastically supporting an occupant, and an air bag (a member that jumps out of the seat pad while partially pushing the seat pad aside) in a seat.

2. Description of Related Art

As this type of vehicle seat, there has been known a vehicle seat including a seat cushion, and a seatback rising from the seat cushion (see Japanese Patent Application Publication No. 2012-25361 (JP 2012-25361 A)). In this vehicle seat, the seatback includes a seat frame (a generally arch-shaped frame body) that forms a seat framework, a seat pad made of foam resin and provided in the seat frame so as to elastically support an occupant, a seat cover that covers the seat pad, and an air bag. The air bag is a sack body that expands due to inflow of air, and is attached to the seat frame so as to be placed on a seat-side portion and a back side of the seat pad.

Further, the seat pad is a generally rectangular member forming a seat outer shape, and includes a sack-body passing portion (corresponding to a jump-out portion). The seat pad is configured such that its center in a width direction is flat so that an occupant can sit thereon, and a side portion of the seat pad (that part of the seat pad which is adjacent to the center of the seat pad in a seat width direction) projects toward a sitting side, which attains an excellent occupant support characteristic. Further, the sack-body passing portion is a hole portion penetrating through the seat pad in its thickness direction, and the sack-body passing portion is opened between the center of the seat pad and the side portion. In the technique as known in the art, at the time of a vehicle collision or the like, the air bag jumps out of the side portion of the seatback so as to protect a lateral side of the occupant. The air bag that expands at this time passes through the sack-body passing portion while pushing the side portion of the seat pad aside, and then jumps out of the seat by partially breaking the seat cover.

SUMMARY OF THE INVENTION

In the meantime, in the configuration of the technique as known in the art, the side portion of the seat pad projects toward the sitting side in consideration of the occupant support characteristic. On this account, in the technique as known in the art, the side portion of the seat pad (a part on the sitting side) may be hard to be pushed aside, which may cause such a possibility that it takes time for the air bag to jump out from the seat pad (an unfolding speed becomes slow). Though the side portion of the seat pad can be generally thinned, the occupant support characteristic may decrease. The present invention provides a vehicle seat that allows an air bag to jump out from a seat pad quickly while maintaining performance of the seat pad to the utmost.

A vehicle seat according to an aspect of the present invention includes: a seat pad forming a seat outer shape and elastically supporting an occupant; and an air bag placed on a back side of the seat pad and configured to be expandable due to inflow of air. The seat pad includes a jump-out portion which is fragile as compared with other parts of the seat pad and from which the air bag jumps out, and an unfolding portion extending from the jump-out portion toward one side of the seat. When the air bag jumps out from the jump-out portion while pushing the unfolding portion aside toward the one side, the unfolding portion is pushed aside while deforming in a bending manner from a part serving as a base point at the time when the unfolding portion is pushed aside by the air bag. The unfolding portion includes a deformable portion that is easy to deform as compared with other parts of the unfolding portion, the deformable portion being placed at the part serving as the base point, and at the time when the air bag jumps out, the deformable portion deforms so as to promote the unfolding portion to deform in a bending manner so that the unfolding portion is pushed aside toward the one side.

In the above aspect, since the unfolding portion is easily pushed aside at the deformable portion, the air bag can jump out from the seat pad quickly without thinning the unfolding portion.

In the above aspect, the deformable portion may be a recessed part. With this configuration, at the time when the air bag jumps out, the unfolding portion can be smoothly pushed aside toward a sitting side while the recessed part is deformed in an expanding manner.

In the above configuration, the seat pad may be a seat pad for a seatback, the deformable portion may be provided continually or intermittently in an up-down direction of the vehicle seat based on an uprising state of the seatback, and an upper part of the deformable portion in the up-down direction of the vehicle seat may have a depth dimension smaller than that of a lower part of the deformable portion. With this configuration, the unfolding portion that is gradually thickened from its upper part toward its lower part and is hard to be pushed aside can be smoothly pushed aside.

In the above aspect, the seat pad may include a back-surface material on a surface facing the air bag, and the deformable portion may be a part where the back-surface material is not provided. With this configuration, the deformable portion easily deforms in a stretching manner as compared with the other parts of the unfolding portion (parts integrated with the back-surface material), so that the unfolding portion can be smoothly pushed aside at the time when the air bag jumps out.

In the above aspect, lubricant may be applied to the deformable portion. With this configuration, the deformable portion maintains a stretching characteristic derived from the seat pad to the utmost, so that the deformable portion is easily stretched as compared with the other parts of the unfolding portion. Since the deformable portion is made slippery by application of the lubricant, when the deformable portion makes contact with other members (the air bag and the like) in a seat, abnormal noise (friction sound or the like) caused by the contact therebetween can be prevented appropriately.

According to the above aspect, the air bag can jump out of the seat pad quickly while performance of the seat pad is maintained to the utmost.

DETAILED DESCRIPTION OF EMBODIMENTS

The following describes an embodiment for carrying out the present invention with reference toFIGS. 1 to 7. Note that, inFIG. 2, a state in the middle of expansion of an air bag is illustrated by an alternate long and two short dashed line. Further, in each of the drawings, a reference sign F is assigned to a vehicle-seat front side, a reference sign B is assigned to a vehicle-seat rear side, a reference sign UP is assigned to a vehicle-seat upper side, a reference sign DW is assigned to a vehicle-seat lower side, a reference sign R is assigned to a vehicle-seat right side, and a reference sign L is assigned to a vehicle-seat left side, appropriately. A vehicle seat2inFIG. 1includes a seat cushion4, a seatback6, and a headrest8. These seat components each include: a seat frame (4F,6F,8F) forming a seat framework; a seat pad (4P,6P,8P) forming a seat outer shape; and a seat cover (4S,6S,8S) covering the seat pad. In the present embodiment, a lower part of the seatback6in an uprising state is connected to a rear part of the seat cushion4in a rising and tilting manner, and the headrest8is disposed on an upper part of the seatback6.

Referring now toFIGS. 1 and 2, the seatback6of the present embodiment includes basic constituents (6F,6P,6S), an air bag10, related constituents (a first unfolding portion21, a second unfolding portion22, a jump-out portion24, a deformable portion26, and a back-surface material30) (details of each portion will be described later). Here, with reference toFIG. 1, the seat frame6F is a generally arch-shaped frame body, and can be formed of a material (metal, hard resin, or the like) that has excellent rigidity. Further, with reference toFIG. 2, the seat pad6P (details thereof will be described later) is a member that can elastically support an occupant, and can be formed of foam resin such as polyurethane foam (density: 10 kg/m3to 60 kg/m3), for example. The seat cover6S is a face material having a pouch-like shape, and can be formed of fabric (woven fabric, knitted fabric, nonwoven fabric) and leather (natural leather, synthetic leather). In the present embodiment, as will be described later, the seat pad6P is placed on the seat frame6F, and then covered with the seat cover6S. Further, the air bag10(details thereof will be described later) is disposed inside a seat, and is placed on a back side of the seat pad6P.

Referring now to a state indicated by the alternate long and two short dashed line inFIG. 2, at the time of a vehicle collision or the like, the air bag10jumps out of the seat from a side portion of the seatback6, so as to protect a lateral part of the occupant. At this time, while the air bag10pushes part of the seat pad6P (mainly, the first unfolding portion21on the sitting side) aside so as to jump out from the jump-out portion24, the air bag10breaks the seat cover6S (typically, a seam part W that is weak) and then jumps out of the seat. In this type of configuration, it is desirable that performance (a support characteristic or the like) of the seat pad6P be maintained to the utmost and the air bag10jump out quickly by causing part of the seat pad6P (mainly, the first unfolding portion21) to be easily pushed aside toward the sitting side. In view of this, in the present embodiment, with a configuration to be described later, the air bag10is configured to jump out from the seat pad6P quickly while maintaining the performance of the seat pad6P to the utmost. The following describes each constituent more specifically.

Referring now toFIGS. 1 and 2, the air bag10(an unexpanded state) of the present embodiment is a member having a generally cube shape elongated in a seat up-down direction, and is disposed inside the side portion of the seatback6. In the present embodiment, the air bag10is fixed to a flat-shaped side frame that forms a side portion of the seat frame6F so as to be placed on a seat side face, and then covered with the seat pad6P (a top-plate side portion6b) to be described later. When the air flows into the air bag10in response to a signal indicative of a vehicle collision so that the air bag10expands and jumps out of the seat, the air bag10protects a body range from a chest of the occupant to a lumbar part of the occupant, for example. Note that a gas supply device is placed inside the air bag10. Gas generant or high-pressure gas is enclosed in the gas supply device (an inflator).

Referring now toFIGS. 1 and 2, the seat pad6P of the present embodiment has a generally rectangular shape (in a front view), and includes a top-plate main portion6a, a top-plate side portion6b, a groove6c, and a back-surface material30(described later). Here, the top-plate main portion6ais a flat part at a center of the seat pad6P in the seat-width direction. Further, the top-plate side portion6bis a projecting part placed on a lateral side of the top-plate main portion6a, and can support a lateral part of the occupant at the time of cornering, for example. With reference toFIG. 2, the top-plate side portion6bof the present embodiment has a generally transverse U shape (in a sectional view) that can cover a side portion of the seat frame6F including the air bag10, and includes the after-mentioned constituents (the first unfolding portion21, the second unfolding portion22, the jump-out portion24). The groove6cis a recessed portion formed on a sitting side of the seat pad6P, and is formed between the top-plate main portion6aand the top-plate side portion6b, so that part of the seat cover6S can be drawn therein via a clip or the like by burying the clip therein, for example.

Referring now toFIGS. 1 and 2, the jump-out portion24is a part which is fragile as compared with the other parts of the seat pad and from which the air bag jumps out. The jump-out portion24can be opened (or expanded) by a pressure or the like of the air bag10at the time of expansion. The jump-out portion24of the present embodiment is constituted by a plurality of through holes penetrating through the seat pad6P in its thickness direction, and a seat-pad portion between through holes adjacent to each other, and the jump-out portion24is provided at a position at which the jump-out portion24can be opposed to the air bag10on a side face of the seat pad6P. With reference toFIG. 1, the jump-out portion24of the present embodiment is configured such that the plurality of through holes is arranged in a row at given intervals in the up-down direction, based on an uprising state of the seatback, but the jump-out portion24may be constituted by a single through hole elongated in the up-down direction. Note that a cut line extending in the up-down direction may be formed in a seat-pad portion between through holes adjacent to each other, so that the jump-out portion24can be easily broken. A linear dimension (a linear dimension from a through hole in an upper end to a through hole in a bottom end) at a formation position of the jump-out portion24is not limited in particular as long as the air bag10can jump out therefrom, but typically, it is desirable that the linear dimension be set larger than a linear dimension of the air bag10, so that the air bag10can be surely unfolded.

With reference toFIG. 2, the first unfolding portion21(an example of an unfolding portion of the present invention) is a part forming a sitting side of the top-plate side portion6b, and the first unfolding portion21includes the after-mentioned deformable portion26and is placed on a front side (one side) of the jump-out portion24. The first unfolding portion21of the present embodiment has a generally transverse L shape (in a sectional view), and includes a first part21athat bends from the top-plate main portion6atoward the sitting side (an F direction inFIG. 2), and a second part21bextending outwardly (an R direction inFIG. 2) toward the seat-width direction from the first part21a. The first unfolding portion21of the present embodiment is gradually thickened toward a seat outer side so as to project toward the sitting side, so that the first unfolding portion21has an excellent support characteristic. Further, the first unfolding portion21is gradually thickened from its upper part to its lower part based on an uprising state of the seatback, and a lower-part side that strongly receives a pressing force from the occupant (a lumbar part of the occupant) is relatively thick (seeFIGS. 4 and 5). Further, the second unfolding portion22is a part (relatively thin) serving as a rear side of the top-plate side portion6b, and the second unfolding portion22has a generally rectangular shape elongated in the seat front-rear direction in a sectional view inFIG. 2, and is placed on a rear side (the other side) of the jump-out portion24.

With reference toFIG. 2, in the present embodiment, the air bag10in a state where the air bag10is placed inside the seat is covered with the first unfolding portion21and the second unfolding portion22. At this time, the second part21bof the first unfolding portion21is bent toward the seat outer side from the first part21aso as to cover a sitting side of the air bag10, and the second unfolding portion22covers a lateral side of the air bag10. At the time when the air bag10jumps out (described later), the second part21bof the first unfolding portion21is mainly pushed aside while curving toward the sitting side (deforming in a bending manner) with its bottom portion being taken as a base point BP. A part serving as the base point BP in the present embodiment is formed at the bottom portion of the second part21bof the first unfolding portion21, and is a thin part (a part having a relatively short minimum distance between a sitting face and a back surface) as compared with other parts of the second part21b.

Here, with reference toFIG. 2, the back-surface material30is a face material attached to a back surface (a surface facing the seat frame6F and the air bag10) of the seat pad6P. A material of the back-surface material30is not limited in particular, but felt and fabric can be exemplified. In the present embodiment, a face material (felt, fabric, or the like) that can be impregnated with a molding material of the seat pad6P is used as the back-surface material30. In the present embodiment, the back-surface material30can be attached to the back surface of the seat pad6P at the same time as molding of the seat pad6P. For example, the back-surface material30is put in a molding device (not shown) for the seat pad6P, and then placed at a position corresponding to the back surface of the seat pad6P. In this state, the molding material (fluid resin) of the seat pad6P is supplied to the device and then foamed, so that the back-surface material30can be integrally attached to the back surface of the seat pad6P while the seat pad6P is molded. The back-surface material30thus attached is impregnated with the molding material of the seat pad6P and the molding material is solidified, so that the back-surface material30is in a hardened state (a state in which the back-surface material30is hard to deform in a stretching manner).

With reference toFIG. 2, the deformable portion26is a part that easily deforms as compared with those other parts of the first unfolding portion21which are provided on a back side of the first unfolding portion21, and the deformable portion26is provided at a part serving as the base point BP at the time when the first unfolding portion21is pushed aside by the air bag10. The deformable portion26of the present embodiment is that part of the first unfolding portion at which the back-surface material30is removed (a part where no back-surface material30is disposed), and the deformable portion26is placed at the bottom portion (serving as the base point BP) of the second part21bof the first unfolding portion21. The deformable portion26is a part that easily deforms as compared with the other parts of the first unfolding portion (parts integrated with the back-surface material30in a solidified state), and the deformable portion26is elongated in the seat up-down direction and has a linear dimension that covers all the jump-out portion24. In the present embodiment, at the time when the air bag10jumps out (described later), the deformable portion26(on the back side of the first unfolding portion21) at the part serving as the base point BP deforms in a stretching manner in the seat width direction. Here, a formation method of the deformable portion26is not limited in particular, but the deformable portion26can be formed at the same time as molding of the seat pad6P, for example. In the present embodiment, at the time of molding of the seat pad6P, the part where no back-surface material30is disposed can be formed by providing that part in a predetermined part (a part corresponding to a formation position of the deformable portion26) inside a forming device. Further, the deformable portion26can be formed by removing the back-surface material30from that part of the first unfolding portion21which serves as the base point BP, after the molding of the seat pad6P.

Referring now toFIG. 2, at the time of a vehicle collision, the air bag10jumps out of the seat so as to protect the lateral part of the occupant. In the present embodiment, while the air bag10mainly pushes the first unfolding portion21aside toward the sitting side so as to jump out from the jump-out portion24, the air bag10breaks the seam part W of the seat cover6S and then jumps out of the seat (see the state indicated by the alternate long and two short dashed line inFIG. 2). At this time, the first unfolding portion21is pushed aside while curving toward the sitting side with a thin bottom portion of the second part21bbeing taken as the base point BP. In the present embodiment, in consideration of an occupant support characteristic, the first unfolding portion21is made so as to be relatively thick (the first unfolding portion21is configured so as to be hard to be pushed aside). In this type of configuration, it is preferable that the air bag10jump out from the seat pad6P quickly while maintaining the occupant support characteristic to the utmost.

In view of this, in the present embodiment, the deformable portion26(a part that relatively easily deforms in a stretching manner) is provided at that part of the first unfolding portion21which serves as the base point BP, so as to promote the first unfolding portion21to deform in a curved manner. Then, at the time when the air bag10jumps out and the first unfolding portion21curves, the second part21bis pushed aside toward the sitting side while the deformable portion26is deformed in a stretching manner in the seat front-rear direction. Accordingly, in the present embodiment, the air bag10that expands smoothly pushes the second part21b(relatively thick) of the first unfolding portion21aside, so that the air bag10can jump out from the seat pad6P quickly.

As described above, in the present embodiment, the first unfolding portion21is easily pushed aside at the deformable portion26. This accordingly allows the air bag10to jump out from the seat pad6P quickly without thinning the first unfolding portion21. Hereby, according to the present embodiment, the air bag10can jump out from the seat pad6P quickly while maintaining the occupant support characteristic to the utmost.

Here, various configurations can be employed as the configuration of the deformable portion, in addition to the above configuration. For example, referring toFIGS. 3 to 5, a deformable portion26A of Modification 1 is a recessed part on a back surface of a first unfolding portion21, and is placed at that part serving as a base point BP which is placed at a bottom portion of a second part21bof the first unfolding portion21. The deformable portion26A is formed as a thinned part having a generally round shape in a sectional view inFIG. 4, and the deformable portion26A is elongated in the seat up-down direction and has a linear dimension that entirely covers a jump-out portion24. In the present modification, at the time when an air bag10jumps out, the first unfolding portion21is pushed aside while curving toward a sitting side with the bottom portion of the second part21bbeing taken as the base point BP. At this time, in the present modification, the first unfolding portion21is smoothly pushed aside toward the sitting side while the deformable portion26A (the recessed part on a back side) is deformed in an expanding manner. Note that, in the present modification, the deformable portion26A is a part where no back-surface material30is disposed, but the back-surface material30can be disposed along the deformable portion26A like another example. By placing the back-surface material30along the deformable portion26A as such, rigidity of this part can be maintained appropriately.

With reference toFIG. 3, the first unfolding portion21of the present modification is gradually thickened from its upper part to its lower part based on an uprising state of the seatback, so that the first unfolding portion21is hard to be pushed aside. In view of this, in the present modification, a depth dimension of the deformable portion26A (the recessed part) can be gradually increased as it goes toward the lower part from the upper part of the first unfolding portion21. For example, in the present modification, the depth dimension of the deformable portion26A (having a generally round shape in a sectional view) is set to be relatively small at the upper part of the first unfolding portion21(seeFIG. 4). When a thickness dimension T1(a minimum distance between a sitting surface and a back surface) on an upper side of the first unfolding portion21is set so as not to be extremely small as such, an extreme reduction of rigidity at this part can be prevented. Further, in a lower part of the first unfolding portion21, the depth dimension of the deformable portion26A is made large, so that a thickness dimension T2in the lower part is substantially equal to the thickness dimension T1of the upper part (seeFIG. 5). As such, in the present modification, the thickness dimension of the first unfolding portion21(at the part serving as the base point BP) is substantially the same at its upper side and its lower side, so that the first unfolding portion21is configured to be easily pushed aside as a whole. Note that that the thickness dimension of the first unfolding portion21is substantially the same means that the thickness dimension is exactly the same, and also means that a difference in the thickness dimension due to some design deviations is allowed. Further, the deformable portion26A is configured such that the upper part and the lower part of the first unfolding portion21have different sectional shapes. For example, in the present modification, a sectional shape of the deformable portion26A at the upper part of the first unfolding portion21is a generally round shape, and a sectional shape of the deformable portion26A at the lower part of the first unfolding portion21is a slit shape.

Further, with reference toFIG. 7, a deformable portion26B of Modification 2 is a part where no back-surface material30is disposed (the same configuration as the above embodiment), and the deformable portion26B is placed at a bottom portion (serving as a base point BP) of a second part21bof a first unfolding portion21. Further, in Modification 2, lubricant is applied to the deformable portion26B (the part where no back-surface material30is disposed), so that the deformable portion26B is slippery (inFIG. 7, a seat-pad portion to which the lubricant is applied is indicated by a thick line). The deformable portion26B to which the lubricant is applied maintains a stretching characteristic derived from a seat pad6P to the utmost, so that the deformable portion26B is easily stretched as compared with the other parts of the first unfolding portion (parts integrated with the back-surface material30). Since the deformable portion26B is thus made slippery by application of the lubricant, when the deformable portion26B makes contact with other members (an air bag10and the like) in a seat, abnormal noise (friction sound or the like) caused by the contact therebetween can be prevented appropriately. This type of lubricant may be a chemical agent that does not extremely obstruct the stretching characteristic of the deformable portion26B, and silicon, grease, a copolymer between silicon and acryl, and a copolymer between silicon and urethane can be exemplified.

The vehicle seat of the present embodiment is not limited to the above embodiment, and other various embodiments can be employed. The present embodiment exemplifies configurations (a shape, a dimension, a formation position, a formation number, and the like) of the deformable portion26and so on, but is not intended to limit the configurations of these portions. For example, the deformable portion can be formed in at least one of the first unfolding portion and the second unfolding portion. Further, the deformable portion can be provided continually or intermittently in the seat up-down direction, and, for example, the deformable portion can be provided only in a part (e.g., a lower part) at which the unfolding portion is particularly thickened. Furthermore, the deformable portion may be configured such that a relatively easily deformable member (other seat pads and the like that are easily stretched as compared with a general seat unfolding portion) is placed at the part serving as the base point (for example, a configuration in which two-color molding is performed). Note that a part serving as the deformable portion may be configured to return to an original state at the time when the air bag is deflated, or may be configured to deform and break (not to return to an original state) at the time when the air bag jumps out.

Further, Modification 1 exemplifies, as the deformable portion26A, a recessed part having a generally round shape and a slit shape (in a sectional view), but this is not intended to limit the configuration of this portion (a shape, a dimension, a formation number, a formation position, and the like). Further, in Modification 1, the first unfolding portion21(a part where the deformable portion26A is formed) is configured such that the thickness dimension T1of the upper part is substantially the same as the thickness dimension T2of the lower part. Differently from this, as long as the deformation of the first unfolding portion is not extremely obstructed, the thickness dimension T1of the upper part may be different from the thickness dimension T2of the lower part (e.g., T2may be larger or smaller than T1). Note that the deformable portion can be buried in other members that are easily stretched as compared with the unfolding portion.

Further, the configuration (a shape, a dimension, a placement position, and the like) of the unfolding portion21or the like can be modified appropriately according to other configurations of the air bag10and the like. For example, the air bag can be configured to jump out of a rear-face side of the seatback. At this time, the jump-out portion is formed on a rear face of the seatback, and the unfolding portion extends from the jump-out portion toward an upper part of the seat (or a lower part of the seat). In this type of configuration, when the air bag jumps out, the unfolding portion is pushed aside toward a seat upper side (or a seat lower side). Note that the part serving as the base point is set appropriately according to the configuration of the unfolding portion and the configuration of the air bag. For example, in a case where the part serving as the base point is formed on the sitting side, the deformable portion can be formed on the sitting side of the unfolding portion.

Further, the configuration (seat components, the air bag, and the like) of the vehicle seat2of the present embodiment can be modified appropriately. Further, in the present embodiment, the seatback is mainly described as an example, but the configuration of the present embodiment is applicable to various seat components such as a seat cushion. Further, the configuration of the present embodiment is applicable to general vehicle seats of a vehicle, an aircraft, an electric railcar, and the like.