JP7568968B2 - Vehicle seats - Google Patents

Description

The present invention relates to a front vehicle seat equipped with an airbag.

Some vehicles have front vehicle seats equipped with an airbag module that deploys rearward (see, for example, Patent Document 1). In the vehicle seat of Patent Document 1, the airbag module is supported by an airbag case and connected to the seatback frame. The airbag case is fastened to the side frames at the left and right edges of its lower end, and is hooked at the center of its upper end to a protrusion provided on the upper frame.

Japanese Utility Model Application Publication No. 7-30163

When the airbag deploys rearward, a forward load is applied to the airbag case. Because the top of the airbag case is hooked to the upper frame at the center of the top end, the rotation of the top of the airbag case is not sufficiently restricted, causing the problem of unstable deployment direction of the airbag.

In view of the above background, the present invention aims to restrict the rotation of a bracket for supporting an airbag relative to a seat back frame in a vehicle seat in which the bracket is connected to the seat back frame.

In order to solve the above problems, a vehicle seat (1) is provided with a seat cushion (3) and a seat back (4), the seat back comprising a seat back frame (7) including a pair of left and right side frames (11) extending in the vertical direction and an upper frame (12) connecting the upper ends of the side frames to each other, an airbag module (43) supported on the seat back frame via a bracket (31), a skin member (9) covering the seat back frame, the bracket and the airbag module from the rear, and a weak part (80) that opens when the airbag is inflated in the skin member at a position facing the airbag module, the bracket being joined to the upper frame at the upper edge with a space between them on the left and right, and joined to the corresponding side frames at the left and right edges.

In this embodiment, the upper edge of the bracket is connected to the upper frame with a gap between them on the left and right, so that the bracket can be prevented from rotating relative to the seat back frame.

In the above embodiment, the bracket may be made of a single plate member integrally including a pair of upper tongue pieces (34) extending from the upper edge and a pair of lower tongue pieces (35) extending from the lower portions of the left and right edges.

This allows the bracket to be made lightweight and inexpensive.

In the above embodiment, the bracket may be substantially trapezoidal in shape with a short side on the upper side.

This allows the upper and lower tongues to be shorter and the bracket to be lighter.

In the above embodiment, the upper tongue piece and the lower tongue piece may each pass behind the seat back frame and be welded to the seat back frame.

This configuration allows the seat back frame to support the forward load applied to the bracket when the airbag deploys.

In the above embodiment, the bracket may have a recess (41) recessed toward the front for accommodating the airbag module, and the recess may overlap the side frame in a side view.

In this embodiment, the recess that houses the airbag module overlaps with the side frame, which reduces the amount of rearward protrusion of the seat back.

In the above embodiment, a through hole (51) may be formed in the bottom wall of the recess, and the airbag module may be fastened to the bottom wall by a fastener (50) that passes through the through hole.

According to this embodiment, the bottom wall of the recess can support the forward load applied to the bracket when the airbag is deployed.

In the above embodiment, a through hole (51) may be formed in the lower side wall of the recess, and the airbag module may be fastened to the side wall by a fastener (50) that passes through the through hole.

In this manner, the fastener does not protrude forward, minimizing the sensation of a foreign object on the back of the seated occupant.

In the above embodiment, the bottom wall (42) of the recess may be flat and inclined downward and rearward with respect to the axial direction of the headrest pillar (28).

According to this aspect, the bottom wall of the recess formed in the bracket is inclined rearward from the top to the bottom, which reduces the sensation of a foreign object that the bracket gives to the back of a seated occupant.

In the above embodiment, it is also preferable that the bracket has an edge wall (36) extending forward from the lower edge thereof.

This aspect increases the rigidity of the bracket.

In the above embodiment, the bracket may have a plurality of lightening holes (38) between the edge wall and the recess.

This allows the bracket to be lightweight.

In the above embodiment, the fragile portion extends laterally, and the bracket has an attachment hole (55) penetrating in the thickness direction between the upper edge and the recess, and a first webbing (81) is provided with one end that is engaged with the attachment hole and the other end that is sewn to the upper skin member that constitutes the fragile portion.

According to this aspect, the weak portion can be opened by applying a load caused by the expansion of the airbag to the first webbing. In addition, since one end of the first webbing is connected to the vicinity of the airbag module, the load is easily transmitted to the first webbing.

In the above embodiment, the fragile portion may include a second webbing (82) that extends laterally, has one end attached to the edge wall, and has the other end sewn to the lower skin member that constitutes the fragile portion.

According to this embodiment, the weak portion can be opened by applying a load caused by the expansion of the airbag to the second webbing. In addition, since one end of the second webbing is connected to the vicinity of the airbag module, the load can be easily transmitted to the second webbing.

In the above embodiment, a blower (56) may be provided to blow air to the front of the bracket.

In this embodiment, the bracket that supports the airbag can also serve as the bracket that supports the blower, reducing the number of parts in the vehicle seat.

According to the above aspect, in a vehicle seat in which a bracket for supporting an airbag is connected to a seat back frame, it is possible to restrict the rotation of the bracket relative to the seat back frame.

In addition, if the bracket is made of a single plate member with an upper tongue and a lower tongue integrally formed, the bracket can be made lightweight and inexpensively.

In addition, by making the bracket approximately trapezoidal with a short side on the upper side, the upper and lower tongue pieces can be shortened and the bracket can be made lighter.

In addition, if the upper and lower tongue pieces each pass behind the seat back frame and are welded to the seat back frame, the forward load applied to the bracket due to the deployment of the airbag can be supported by the seat back frame.

In addition, the bracket has a recess that faces forward to accommodate the airbag module, and if the recess overlaps the side frame in a side view, the amount that the seat back protrudes rearward can be reduced.

In addition, in an embodiment in which a through hole is formed in the bottom wall of the recess and the airbag module is fastened to the bottom wall by a fastener that passes through the through hole, the bottom wall of the recess can support the forward load applied by the deployment of the airbag.

In addition, by forming a through hole in the lower side wall of the recess and fastening the airbag module to the lower side wall of the recess with a fastener that passes through the through hole, the fastener does not protrude forward, and the sensation of a foreign body in the back of the seated occupant can be reduced.

In addition, if the bottom wall of the recess is in the shape of a flat plate with an inclination that recedes from its top to its bottom relative to the axial direction of the headrest pillar, the bracket can reduce the sensation of a foreign object on the back of a seated occupant.

In addition, if an edge wall extending forward is provided on the lower edge of the bracket, the rigidity of the bracket can be increased.

In addition, if the bracket has multiple lightening holes between the edge wall and the recess, the bracket can be made lighter.

In addition, in an embodiment having a first webbing, one end of which is engaged with the mounting hole and the other end of which is sewn to the upper skin member constituting the weak portion, the weak portion can be opened by applying a load caused by the expansion of the airbag to the first webbing. Since one end of the first webbing can be joined near the airbag module, the load can be easily transmitted to the first webbing.

In addition, in an embodiment having a second webbing, one end of which is fastened to the edge wall and the other end of which is sewn to the lower skin material constituting the weak portion, the weak portion can be opened by applying a load caused by the expansion of the airbag to the second webbing. Since one end of the second webbing can be joined near the airbag module, the load can be easily transmitted to the second webbing.

In addition, in an embodiment where a blower for blowing air is provided on the front surface of the bracket, the bracket supporting the airbag can also serve as a bracket for supporting the blower, thereby reducing the number of parts in the vehicle seat.

FIG. 1 is an explanatory diagram showing the deployment of an airbag in a vehicle seat; Rear view of the vehicle seat frame Rear view of a vehicle seat FIG. 4 is a cross-sectional view of the vehicle seat according to the first embodiment taken along line IV-IV of FIG. FIG. 11 is a cross-sectional view of a vehicle seat according to a second embodiment; FIG. 11 is a cross-sectional view of a vehicle seat according to a third embodiment; 1A is a cross-sectional view of a vehicle seat according to another embodiment in which (A) the arrangement of the second webbing and (B) the arrangement of the first webbing are different from those of the first embodiment; 13A and 13B are rear views of a vehicle seat according to another embodiment in which a pad member is provided with two intersecting slits and a substantially H-shaped slit; 1A is a cross-sectional view of a vehicle seat according to another embodiment in which a backboard having a thin portion and a backboard having a slit are provided; 1A is a cross-sectional view of a vehicle seat according to another embodiment in which the outer case is omitted, and FIG. 1B is a cross-sectional view of a vehicle seat according to another embodiment in which the retainer and the cover are omitted.

Below, two embodiments of the vehicle seat according to the present invention applied to an automobile will be described with reference to the drawings.

First Embodiment
1, a vehicle seat 1 according to a first embodiment of the present invention constitutes a first row front seat of an automobile. The seat has a seat cushion 3 provided on a floor 2 of the automobile, a seat back 4 supported on a rear portion of the seat cushion 3, and a headrest 5 provided on an upper portion of each seat back 4.

As shown in FIG. 2, the seat back 4 has a seat back frame 7 as a skeleton, a pad member 8 supported by the seat back frame 7, and a skin member 9 provided on the surface of the pad member 8 and constituting the outer surface of the seat back 4.

The seatback frame 7 has a pair of left and right side frames 11 extending vertically, an upper frame 12 extending horizontally and connecting to the upper ends of the left and right side frames 11, and a lower frame 13 extending horizontally and connecting to the lower parts of the left and right side frames 11. The upper frame 12 and the upper side frame upper parts 14 constituting the upper parts of the left and right side frames 11 are formed by bending a single circular pipe material into an inverted U-shaped frame shape. The lower side frame lower parts 15 constituting the lower parts of the side frames 11 are each formed of a sheet metal material and welded to both ends of the pipe material. A pair of support members 16 are hung vertically between the left and right side frames 11. A plate-shaped pressure-receiving member 17 that supports the back of the occupant so that it can move backwards is connected to the front side of the support member 16.

As shown in FIG. 2, the upper part of the seatback frame 7 is formed by the upper frame 12 and the upper parts 14 of the left and right side frames, and has a generally trapezoidal shape when viewed from behind.

The upper frame 12 has a flat front side surface 21 on the front side of the middle part on the left and right sides. The front side surface 21 is formed by compressing and deforming a circular pipe material so that its cross section becomes semicircular. A pair of pillar support brackets 22, one on the left and one on the right, are welded to the front side surface 21. Each pillar support bracket 22 is formed in a square tube shape with both ends open. The pillar support brackets 22 have their respective axes extending substantially vertically and are arranged at intervals from each other on the left and right. A pillar support member 23 is inserted into the pillar support bracket 22. The pillar support member 23 has a cylindrical portion 24 and a flange portion 25 that protrudes laterally from the upper end of the cylindrical portion 24. The axis direction of the cylindrical portion 24 is approximately parallel to the extension direction of the side frame 11.

The headrest 5 comprises a headrest body 27 and a pair of left and right pillars 28 that protrude from the headrest body 27. By fitting the pillars 28 into the tubular portion 24, the headrest 5 is supported on the seat back frame 7 so as to be displaceable along the axis of the tubular portion 24. The flange portion 25 is provided with a locking means (not shown) for fixing the insertion position of the pillars 28 relative to the tubular portion 24. The headrest 5 is fixed in a predetermined position by the locking means.

A bracket 31 is connected to both side frames 11 and the upper frame 12. The bracket 31 is located in the upper half of the seatback frame 7. The bracket 31 is in the shape of a plate facing generally in the front-rear direction. The bracket 31 is made of a single plate member drawn from a single piece of sheet metal, and has a plate-shaped main portion 30 with a main surface facing forward and backward, a pair of upper tongue pieces 34 on the left and right that extend upward in a strip shape from the upper edge of the main portion 30, and a pair of lower tongue pieces 35 on the left and right that extend outward from the lower left and right parts of the main portion 30. The main portion 30 is made up of a central portion 32 that forms its upper portion, and a base portion 33 provided below the central portion 32.

The central portion 32 is generally trapezoidal in shape, narrowing in width in the left-right direction toward the top when viewed from the rear. The central portion 32 is generally the same shape as the upper portion of the seatback frame 7.

The upper tongue pieces 34 extend upward from the left and right ends of the upper edge of the central portion 32, and are formed with a gap between them. The upper tongue pieces 34 are arranged symmetrically with respect to the center line in the left-right direction of the seatback frame 7. The upper ends of the upper tongue pieces 34 are curved to fit along the rear surface of the upper frame 12 and are welded to the upper frame 12. The lower tongue pieces 35 are curved to fit along the rear surface of the upper side frame 14 and are welded to the side frame 11. In this embodiment, the upper tongue pieces 34 are welded to the upper part of the rear surface of the upper frame 12 (broken line part in FIG. 2), and the lower tongue pieces 35 are welded to the left and right outer parts of the rear surface of the upper side frame 14 (broken line part in FIG. 2).

As shown in FIG. 4, the lower edge of the base portion 33 is provided with an edge wall 36 that extends forward along the entire lower edge. A pair of left and right weak parts 37 are formed at the boundary between the base portion 33 and the lower tongue piece 35. In this embodiment, the bracket 31 is bent at the weak parts 37 so that they protrude forward in a U-shape. A number of lightening holes 38 are formed at appropriate positions in the base portion 33 to reduce the weight of the bracket 31.

A recess 41 is formed in the rear surface of the central portion 32, approximately at the center, and recessed forward. The bottom of the recess 41 overlaps the side frame 11 in side view. The recess 41 is defined by a flat recess bottom wall 42 that faces approximately in the front-to-rear direction, and a side wall that surrounds the recess bottom wall 42. The recess bottom wall 42 is inclined downward and rearward with respect to the axial direction of the pillar 28 in side view. The recess bottom wall 42 has a generally rectangular shape extending left and right in rear view, and the recess 41 has a generally rectangular parallelepiped shape.

The outer case 40 made of resin is housed in the recess 41. The outer case 40 is generally rectangular parallelepiped-shaped and extends left and right. The outer case 40 has a bottom wall 40B facing the front-rear direction and a side wall 40S surrounding the bottom wall 40B. The outer case 40 has a storage recess 40R defined by the bottom wall 40B and the side wall 40S. The storage recess 40R is recessed toward the front and opens toward the rear. Locking claws 40C are provided at predetermined positions on the upper and lower surfaces of the outer case 40, protruding outward in the vertical direction. Locking holes are provided in the upper and lower walls of the recess 41 at positions corresponding to the locking claws 40C and engage with the locking claws 40C.

A forward-projecting mating protrusion 40P is provided at a predetermined position on the front surface of the outer case 40, and a positioning hole is provided in the bottom wall 42 of the recess at a position corresponding to the mating protrusion 40P. When the outer case 40 is joined to the recess 41, the outer case 40 can be easily positioned in the correct position by engaging the locking claw 40C with the locking hole and inserting the mating protrusion 40P into the positioning hole.

An extension 40E is provided at the opening edge of the outer case 40, extending approximately perpendicularly to the side wall 40S. The extension 40E extends outward beyond the opening edge that defines the opening portion of the recess 41 of the bracket 31. At least a portion of the opening edge of the recess 41, and preferably all of the opening edge, is covered from the rear by the extension 40E.

An airbag module 43 is housed in the housing recess 40R. The airbag module 43 abuts against the bottom wall 40B, and is housed inside the recess 41. The airbag module 43 includes an airbag 45, an inflator 46 that inflates the airbag 45, and a case 47 that houses the airbag 45 and the inflator 46.

The case 47 is roughly rectangular and includes a retainer 48 with a recess that opens toward the rear, and a lid 49 that closes the opening of the recess.

The inflator 46 is generally cylindrical. The inflator 46 is housed in the lower half of the retainer 48, more specifically, in a recess of the retainer 48 extending left and right at the lower front corner, and is connected to the retainer 48. The airbag 45 is housed in the recess of the retainer 48 in a folded state. The airbag 45 is positioned so as to cover the inflator 46 from above.

The retainer 48 has an upper wall 44 that defines the recess. The upper wall 44 has a surface that faces downward and faces the inflator 46 from above and below. An airbag 45 is disposed between the upper wall 44 and the inflator 46.

The lid body 49 is made of resin. The lid body 49 has a generally rectangular plate-shaped lid body main body 49B with a main surface facing the front-rear direction, and a lid body locking portion 49L that extends forward from the top, bottom, left, and right ends of the lid body main body 49B and has locking claws at its end. Locking holes are provided in the top, bottom, left, and right walls of the retainer 48, and the lid body 49 is connected to the retainer 48 by the locking claws engaging with the locking holes. A groove extending left and right is formed on the inside of the lid body main body 49B. The lid body main body 49B is thinner at the groove 53 than other parts. The groove 53 extends in the up and down direction from the left and right ends, respectively, and extends to the top and bottom ends of the lid body main body 49B.

A hinge 49H is formed at the connection between the lid body 49B and the lid locking portion 49L, and the lid body 49 is hinged to the upper and lower edges of the opening of the retainer 48. When a load is applied to the lid body 49 due to the inflation of the airbag 45, the lid body 49 splits open along the groove 53. Thus, the groove 53 functions as a deployment opening. When the lid body 49 splits open, the upper and lower rear sides of the lid body 49 rotate about the upper and lower edges, respectively, as axes, and the case 47 opens. The opening edge of the recess 41 of the bracket 31 is covered from the rear by the extension 40E, so that when the airbag 45 inflates, the airbag 45 does not directly abut against the opening edge of the recess 41, preventing damage to the airbag 45.

The front surface of the retainer 48 is provided with a male threaded portion 50 that protrudes forward. The bottom wall of the outer case 40 and the bottom wall 42 of the recess are provided with through holes 51, 44T that penetrate at positions corresponding to the male threaded portion 50. After the male threaded portion 50 is passed through the two through holes 51 in the outer case 40 and the bottom wall 42 of the recess, a nut 52 is attached to the male threaded portion 50, thereby fastening the airbag module 43 together with the outer case 40 to the bracket 31. After fastening, the case 47 is positioned so that it overlaps the side frame 11 in a side view.

A pair of left and right mounting holes 55 are formed at the top of the central portion 32 and above the recess 41, penetrating through the thickness direction.

A blower 56 is attached to the front surface of the bottom wall 42 of the recess. The blower 56 includes a blower case 57, a motor 58 housed in the blower case 57, and a fan 60 connected to a rotating shaft 59 of the motor 58.

The blower case 57 is substantially rectangular and has a surface facing the front-rear direction. An opening is formed in the front wall of the blower case 57. A through hole penetrating the blower case 57 from front to rear is formed at a predetermined position, and a screw hole is formed at a position corresponding to the through hole in the bottom wall 42 of the recess. The blower case 57 is connected to the front of the bottom wall 42 of the recess approximately at the center in the left-right direction by a screw that passes through the through hole and connects to the screw hole. The front wall of the blower case 57 is approximately parallel to the bottom wall 42 of the recess, and the blower case 57 is disposed between the left and right pillars 28. In this embodiment, the width of the blower case 57 in the front-rear direction is sufficiently thin, and the front wall of the blower case 57 is located rearward of the pillar 28 in a side view.

A cable (not shown) is connected to the motor 58 to supply power from outside the vehicle seat 1. The motor 58 is driven by the supplied power, causing the fan 60 to rotate. Air is sprayed forward by the rotation of the fan 60.

The pad member 8 is formed from a flexible cushioning material such as polyurethane foam. The pad member 8 has a front surface 65 that constitutes a backrest surface 64 that faces the back of the occupant, an upper surface 66 that extends rearward from the upper edge of the front surface 65, side surfaces 67 that extend rearward from the left and right side edges of the front surface 65, and a rear surface 68 that extends downward from the rear end of the upper surface 66.

The front surface 65 extends vertically and is a generally rectangular plate with a predetermined thickness in the front-to-rear direction. The rear surface of the front surface 65 abuts against the front surfaces of both side frames 11, the upper frame 12, and the pressure-receiving member 17. The front surface 65 has a ventilation hole 69 formed in front of the blower 56, which penetrates from front to back. The air sprayed from the blower 56 passes through the ventilation hole 69 and reaches the backrest surface 64.

In a side view, the upper surface portion 66 extends rearward from the upper edge of the front surface portion 65 to the rear edge of the upper frame 12. Through holes 70 that penetrate vertically are formed in the upper surface portion 66 in portions that correspond to the upper ends of the left and right pillar support brackets 22. A corresponding pillar support bracket 22 is inserted into each through hole 70.

The side surface portions 67 extend rearward from the left and right side edges of the front surface portion 65 along the left and right outer surfaces of the side frame 11, respectively, and reach the rear surface of the side frame 11.

The rear surface portion 68 extends downward from the rear end of the upper surface portion 66 and reaches the lower end of the bracket 31. A first slit 71 is formed in the rear surface portion 68 behind the bottom wall 42 of the recess, more specifically, behind the groove 53, penetrating in the thickness direction. The first slit 71 extends in the penetrating direction generally perpendicular to the bottom wall 42 of the recess. As shown in FIG. 3, the first slit 71 extends in the left-right direction from between the left side frame 11 and the left wall of the recess 41 to between the right side frame 11 and the right wall of the recess 41. The left-right width of the first slit 71 is preferably greater than the left-right width of the recess 41 and greater than the left-right width of the central portion 32.

Two second slits 72 are formed in the rear surface 68 behind each mounting hole 55, penetrating in the thickness direction. Each second slit 72 is preferably inclined in the penetrating direction so as to approach the opening portion in the surface of the first slit 71 toward the rear. The left-right width of each second slit 72 is approximately equal to the left-right width of each mounting hole 55.

As shown in Figures 3 and 4, the cover member 9 is formed into a bag shape by combining a front sheet material 75 that integrally covers the surfaces of the front portion 65, the top portion 66, the side portions 67, and the rear portion 68 of the pad member 8, and a rear sheet material 76 that forms the rear surface of the seat back 4.

The front sheet material 75 is formed by sewing together a number of pieces formed from sheet-like materials such as cloth or leather. The front sheet material 75 has a front piece covering the surface of the front portion 65, side pieces 77 covering the surfaces of the left and right side portions 67, and an upper piece 78 covering the surfaces of the top portion 66 and the rear portion 68. The upper edge of the front piece and the front edge of the upper piece 78, the left and right side edges of the front piece and the front edges of the side pieces 77, and the upper edge of the side piece 77 and the left and right side edges of the upper piece 78 are sewn together. The rear sheet material 76 is formed by a rear piece 79 formed from a sheet-like material. The rear piece 79 has a generally rectangular shape extending vertically. The upper edge of the rear piece 79 and the rear edge of the upper piece 78 are sewn together to form a sewn portion 80. The sewn portion 80 functions as a weak portion that breaks under a smaller load than other sewn portions.

The stitching portion 80 is disposed rearward of the opening on the rear end side of the first slit 71. The stitching portion 80 is located rearward of the upper half of the recess 41, more specifically, approximately rearward of the upper wall 44 of the retainer 48. Thus, the stitching portion 80 is located above the inflator 46. The stitching portion 80 is formed to extend left and right. The left and right ends of the stitching portion 80 are located respectively on the left and right outer sides of the recess 41. It is preferable that the left and right ends of the stitching portion 80 are located on the left and right outer sides of the main portion 30 of the bracket 31.

The upper side edge of the rear piece 79 and the upper side edge of the side piece 77 are sewn together. The lower side edge of the rear piece 79 and the lower side edge of the side piece 77 are connected openably and closably by fasteners, hook-and-loop fasteners, snap fits, or the like. This allows the cover member 9 to be connected to the seat back 4 by connecting the rear piece 79 and the side piece 77 after the cover member 9 is placed over the seat back frame 7 and the pad member 8.

Between the bracket 31 and the skin member 9, a first webbing 81 and a second webbing 82 are provided to regulate the deployment direction of the airbag 45. The first webbing 81 and the second webbing 82 are each formed of a sheet-like material having less elasticity than the skin member 9. One end side of the first webbing 81 and the second webbing 82 is respectively connected to the bracket 31 above and below the airbag module 43. A pair of left and right clips 83 are connected to one end side of the first webbing 81. Each clip 83 is fitted into a corresponding mounting hole 55. A hook 84, which is a J-shaped hook member, is connected to one end of the second webbing 82. Each hook 84 is hooked to the edge wall 36. The first webbing 81 extends rearward from each clip 83, passes through the second slit 72, and reaches the vicinity of the upper side of the stitching portion 80. The second webbing 82 extends rearward along the lower and rear edges of the rear surface portion 68, and then extends upward to reach the lower side of the seam 80. The other end of the first webbing 81 and the lower edge of the upper piece 78 are sewn together near the seam 80. The other end of the second webbing 82 and the upper edge of the rear piece 79 are sewn together near the seam 80.

Next, the operation of the vehicle seat 1 will be described. A frontal collision or the like causes forward acceleration and load to be applied to the rear seat occupant. In order to detect such load applied to the rear seat occupant, for example, a sensor 92 may be provided that detects the load applied to the seat belt 91 worn by the rear seat occupant.

When the acceleration of the rear seat passenger or the load applied to the seat belt 91 exceeds a predetermined value, gas is released from the inflator 46. The airbag 45, which is inflated upward by the gas released from the inflator 46, is guided rearward by the lower surface of the upper wall 44 of the retainer 48. Thus, the upper wall 44 of the retainer 48 functions as a guide wall that guides the inflation direction of the airbag 45. When the airbag 45 inflates rearward, a load is applied to the lid 49, which is torn at the groove 53, and the case 47 of the airbag module 43 is opened. The airbag 45 protrudes from the case 47, is guided by the first webbing 81 and the second webbing 82, passes through the first slit 71, and reaches the stitching 80. At this time, the stitching 80 is broken by the load from the airbag 45, and an opening is formed in the skin member 9. The airbag 45 protrudes from the rear surface of the seat back 4 through the opening, inflates rearward and diagonally upward, and then deploys downward and rearward. When deployed, the airbag 45 has an upwardly convex arch shape (dotted line in FIG. 1). Therefore, the airbag 45 can be deployed in front of the occupant's upper body regardless of the distance between the vehicle seat 1 and the rear seat. When the rear seat is close to the vehicle seat 1, the airbag 45 is folded, so the rearward load applied to the occupant due to the deployment of the airbag 45 can be reduced.

Next, the effects of the vehicle seat 1 will be described. As shown in FIG. 4, the airbag module 43 is covered with a cover member 9 and disposed inside the seat back 4. Because the airbag module 43 is not exposed on the rear surface of the seat back 4, the design of the vehicle seat 1 can be improved. In addition, because the airbag module 43 is covered with a pad member 8, the feel of the back surface of the vehicle seat 1 is improved.

Since the airbag module 43 is housed in the recess 41, the amount of protrusion of the airbag module 43 from the rear surface of the seat back 4 can be reduced. The front part of the case 47 of the airbag module 43 is disposed below the upper frame 12, in a position overlapping with the side frame 11 in a side view. Therefore, the airbag module 43 is disposed further forward with respect to the seat back frame 7, compared to when the entire case 47 is positioned behind the side frame 11. This makes it possible to reduce the amount of protrusion of the seat back 4 rearward.

The airbag 45 is inflated along the first slit 71 by gas from the inflator 46. This inflation applies an upward load to the first webbing 81 and a downward load to the second webbing 82. The loads applied to the first webbing 81 and the second webbing 82 are transmitted to the stitching 80, and the upper and lower vicinity of the stitching 80 of the skin member 9 are pulled from above and below, respectively, causing the stitching 80 to open. The airbag 45 deploys behind the seat back 4 through the first slit 71 and the open stitching 80.

By forming the second slit 72, the first webbing 81 can be positioned so that it extends in a generally straight line from the rear of the mounting hole 55 to the front of the sewn portion 80. This allows the length of the first webbing 81 in the front-to-rear direction to be shortened. This makes it easier for the load applied to the first webbing 81 to be transmitted to the sewn portion 80, making it easier for the sewn portion 80 to open.

The second webbing 82 extends along the lower and rear edges of the pad member 8, reaching near the lower portion of the seam 80. Therefore, after the pad member 8 and the cover member 9 are assembled and placed over the seat back frame 7, the hook 84 can be hooked onto the edge wall 36 from below. This makes it easy to attach the second webbing 82.

The first webbing 81 is provided with a pair of clips 83, and the first webbing 81 can be easily attached to the bracket 31 by inserting the clips 83 into the mounting holes 55. In addition, because the first webbing 81 is attached to two mounting holes 55 that are aligned to the left and right, the area of the first webbing 81 that receives the load due to the expansion of the airbag 45 is expanded in the left and right direction, making it easier for the load due to the expansion of the airbag to be applied to the seam 80.

Since one end side of the first webbing 81 and the second webbing 82 is engaged near the airbag module 43 of the bracket 31, the load is easily transmitted to the first webbing 81 and the second webbing 82. In addition, the first webbing 81 and the second webbing 82 can concentrate the load caused by the deployment of the airbag 45 on the stitching portion 80, and the stitching portion 80 can be reliably broken when the airbag 45 is deployed.

The airbag 45 inflates rearward relative to the recess 41. When viewed from behind, the center portion of the stitching 80 overlaps with the recess 41, so that the airbag 45 inflating rearward easily passes through the stitching 80.

As shown in FIG. 3, the seam 80 extends laterally on the rear surface of the seat back 4. This allows the width (horizontal width) of the airbag 45 in the left-right direction when deployed to be increased, allowing it to accommodate a wide range of left-right positions of rear seat occupants. The left and right ends of the seam 80 are located on the left and right outer sides of the recess 41, respectively, and preferably the left and right ends of the seam 80 are located on the left and right outer sides of the main part 30 of the bracket 31. In this way, by increasing the width of the seam 80, the airbag 45 inflated rearward can easily pass through the seam 80. The width of the airbag 45 in the deployed state can also be increased, allowing it to accommodate a wide range of left-right positions of rear seat occupants.

As shown in FIG. 2, the bracket 31 is connected to the upper frame 12 at the left and right upper tongue pieces 34 at intervals on the left and right. Therefore, rotation of the upper part of the bracket 31 about an axis extending in the generally vertical direction is restricted. This makes it difficult for the bracket 31 to come off the seat back frame 7, and the connection between the bracket 31 and the seat back frame 7 can be made stronger.

Because the bracket 31 is formed from a single plate member, it is lightweight and can be formed at low cost. The bracket 31 is generally trapezoidal with a short side on the upper side, and is roughly the same shape as the upper part of the seat back frame 7. This allows the upper tongue piece 34 and the lower tongue piece 35 to be shortened. In addition, the upper right corner and upper left corner of the bracket 31 are omitted, making the bracket 31 lighter.

When the airbag 45 deploys and when a rear seat occupant collides, a forward load is applied to the bracket 31. Because the upper tongue piece 34 is positioned along the rear surface of the upper frame 12 and the lower tongue piece 35 is positioned along the rear surface of the upper side frame 14, a rearward load is applied to the upper tongue piece 34 and the lower tongue piece 35 from the rear surface of the upper frame 12 and the rear surface of the upper side frame 14. Therefore, the bracket 31 is supported by the seat back frame 7 and can withstand the forward load.

The airbag module 43 is fastened to the bottom wall 42 of the recess. When the airbag 45 is deployed, a load is applied to the airbag module 43 in the forward direction. Because the airbag module 43 is fastened to the bottom wall 42 of the recess, the bracket 31 resists the load, and the airbag module 43 is supported by the bracket 31. In addition, because the airbag module 43 is fastened to the bottom wall 42 of the recess, it is easier to fasten the airbag module 43 to the bracket 31.

The airbag module 43 is located in the upper half of the seatback frame 7. Therefore, since the airbag module 43 is positioned in front of the upper body of the rear seat occupant, the airbag 45 can be deployed in front of the upper body of the rear seat occupant, thereby protecting the upper body of the rear seat occupant. In addition, since the stitching portion 80 is located behind the upper half of the recess 41, the airbag 45 can be deployed from a higher position on the seatback 4.

The bracket 31 is positioned rearward of the pillar 28. Therefore, the bracket 31 can be attached without changing the position of the pillar 28.

The load applied when seated can cause the occupant's back to move rearward of the axis of the pillar 28. Even in this case, the recess bottom wall 42 is inclined downward and rearward, so that the recess bottom wall 42 does not interfere with the occupant's back, and the occupant's feeling of a foreign body can be reduced. In addition, the bracket 31 is positioned above the pressure-receiving member 17, so the bracket 31 can prevent the occupant's back from feeling a foreign body.

The bottom portion 33 connects the side frames 11 to the left and right via the lower tongue pieces 35, and therefore functions as a cross member that increases the rigidity of the seatback frame 7. To increase the rigidity of the seatback frame 7, it is preferable that the bottom portion 33 is joined to the side frame 11 at a position that is 5 to 20 percent of the total length of the side frame 11 from the upper end of the side frame 11. If the side frame 11 is formed with a bent portion 93 that bends inwardly to the left and right, it is preferable that the bottom portion 33 is joined to the side frame 11 above the bent portion 93.

The rigidity of the base portion 33 is increased by the edge wall 36. The lower wall that defines the recess 41 faces the edge wall 36, and the lower portion of the bracket 31 has a U-shape that faces forward in side view, further increasing its rigidity. By increasing the rigidity of the lower portion of the bracket 31, the connection between the side frames 11 becomes stronger, and the rigidity of the seatback frame 7 can be further increased.

By providing the blower 56 in the vehicle seat 1, air is blown out from the ventilation holes 69 in the seat back 4 toward the seated occupant, improving seating comfort. Because the blower 56 is connected to the bracket 31 that supports the airbag 45, there is no need to provide a bracket 31 to support the blower 56, which reduces the number of parts and simplifies the vehicle seat 1.

When the airbag 45 deploys, the rear seat passenger may collide with the airbag 45, and a forward load may be applied to the bracket 31. At this time, the forward load applied to the bracket 31 is absorbed by the deformation of the weak portion 37 of the bracket 31. This reduces the load applied to the rear seat passenger. It also prevents a load from being applied to the passenger in the vehicle seat 1 due to a collision by the rear seat passenger.

<<Second embodiment>>
The vehicle seat 1 according to the second embodiment is different from the first embodiment in that the airbag module 43 is fastened to a recess lower wall 96 that defines the lower part of the recess 41 and faces the up-down direction, as shown in FIG. 5. The male thread portion 50 provided on the airbag module 43 extends downward. The recess lower wall 96 is provided with a through hole 51 at a position corresponding to the male thread portion 50. The side wall 40S of the outer case 40 is provided with a through hole 40T at a position corresponding to the male thread portion 50. The male thread portion 50 is passed through each of the through holes 51, 41T, and a nut 52 is coupled to the male thread portion 50, whereby the airbag module 43 is fastened to the recess lower wall 96. The airbag module 43 may be fastened to any of the side walls surrounding the recess bottom wall 42.

Since the airbag 45 deploys above and behind the seat back 4, a downward load may be applied to the recess 41 when the airbag 45 deploys. By fastening the airbag module 43 to the lower wall 96 of the recess, the bracket 31 can resist the downward load when the airbag 45 deploys. In addition, because the male thread portion 50 does not protrude forward, the sensation of a foreign object on the back of the seated occupant can be reduced.

<<Third embodiment>>
6, the vehicle seat 1 according to the third embodiment is different from the first embodiment in that the second slit 72 is not provided, and only the arrangement of the first webbing 81 and the second webbing 82 is different. The first webbing 81 is fixed to the mounting hole 55 by a clip 83 at one end, extends downward along the back surface of the pad member 8, and reaches the seam 80 through the first slit 71. The second webbing 82 is hooked to the edge wall 36 by a hook 84 at one end, extends upward along the back surface of the pad member 8, and reaches the seam 80 through the first slit 71. Even when arranged in this manner, the first webbing 81 and the second webbing 82 restrict the deployment direction of the airbag 45 from above and below, respectively, so that the deployment direction of the airbag 45 is controlled to face the seam 80.

Although the description of the specific embodiment is finished above, the present invention is not limited to the above embodiment and can be widely modified. For example, the shape of the bracket 31 is not limited to the above embodiment and can be appropriately changed. In the above embodiment, the second webbing 82 is hooked to the edge wall 36 of the bottom portion 33 at one end, but it may be fitted into the lightening hole 38 by a clip, for example. In the above embodiment, the first webbing 81 and the second webbing 82 are provided on the vehicle seat 1, but it may be an embodiment in which either the first webbing 81 or the second webbing 82 is provided. In the first embodiment, as shown in FIG. 7(A), only the second webbing 82 may be modified to fit along the back surface of the pad member 8, or only the first webbing 81 may be modified to fit along the back surface of the pad member 8, as shown in FIG. 7(B).

In the above embodiment, the stitching 80 was formed to extend left and right on the rear surface of the seat back 4, but by dividing the side pieces 77 into upper and lower parts and providing both left and right ends of the stitching 80 on the left and right outer surfaces of the side portion 67, the stitching 80 may be formed to extend left and right from both left and right side surfaces of the seat back 4 through the rear surface.

In the above embodiment, the first slit 71 is formed to extend left and right in the pad member 8, but this is not limited to the embodiment. The pad member 8 may be provided with a third slit 100 that intersects with the first slit 71 (FIG. 8(A)). Also, third slits 101 that extend up and down from both ends of the first slit 71 may be further provided (FIG. 8(B)). By providing the third slits 100, 101, the pad member 8 is more easily opened around the first slit 71, and the time required for the airbag 45 to deploy can be shortened.

In the above embodiment, the rear sheet material 76 formed of a sheet-like member is provided on the rear surface of the seat back 4. However, as shown in FIG. 9A, instead of the rear sheet material 76, a backboard 110 formed of resin or the like may be provided. The backboard 110 is formed in a plate shape having main surfaces at the front and rear. The upper end of the backboard 110 is bent backward and upward along the rear surface portion 68. The backboard 110 is supported by the side frame 11. At the upper portion of the backboard 110, a thin-walled portion 111 is formed so as to extend left and right in a rear view. The thin-walled portion 111 is preferably formed approximately behind the groove 53 of the airbag module 43. When the airbag 45 deploys, a load is applied from the airbag 45 to the backboard 110. Due to the load, the backboard 110 is bent backward at the thin-walled portion 111. The bending of the backboard 110 creates a gap between the backboard 110 and the cover member 9 that covers the rear surface 68. The airbag 45 deploys behind the seat back 4 through the gap.

9B, the backboard 120 may be provided with a slit 121 that is torn by the load from the airbag 45 when the airbag 45 is deployed. The slit 121 is disposed behind the airbag module 43. The slit 121 may be a groove formed in the front surface of the backboard 120. The slit 121 may be substantially H-shaped in rear view, including a portion extending left and right and portions extending up and down from both ends. When the airbag 45 is deployed, the backboard 120 is bent backward at the portion extending left and right, forming an opening in the backboard 120. The airbag 45 deploys behind the seat back 4 through the opening.

In the above embodiment, the outer case 40 is provided in the recess 41, but as shown in FIG. 10(A), the curvature of the opening edge 130 of the recess 41 may be increased to prevent damage to the airbag 45 during inflation. Also, as shown in FIG. 10(B), the outer case 40 may be fitted into the recess 41, and the airbag 45 and the inflator 46 may be housed in the housing recess 40R of the outer case 40.

1: Vehicle seat 3: Seat cushion 4: Seat back 7: Seat back frame 9: Cover member 11: Side frame 12: Upper frame 28: Pillar (headrest pillar)
31: bracket 34: upper tongue portion 35: lower tongue portion
36: Edge wall 41: Recess 42: Recess bottom wall 43: Airbag module 45: Airbag 50: Male thread (fastener)
51: Through hole 55: Mounting hole 56: Blower 80: Stitched portion (weakened portion)
81: First webbing 82: Second webbing

Claims (10)

A vehicle seat having a seat cushion and a seat back,
The seat back,
a seat back frame including a pair of left and right side frames extending in a vertical direction and an upper frame connecting upper ends of the left and right side frames to each other;
an airbag module supported on the seat back frame via a bracket;
a cover member that covers the seat back frame, the bracket, and the airbag module from a rear surface thereof;
the cover member has a weakened portion that is to be opened by the inflation of the airbag at a position facing the airbag module,
The bracket is coupled to the seat back frame,
The bracket has a recess that is recessed forward,
The airbag module is housed in the recess,
The recess is formed by a flat bottom wall and a side wall that surrounds the bottom wall and includes a portion located below the airbag,
the airbag module includes the airbag and an inflator that introduces gas into the airbag to cause the airbag to protrude from a rear surface of the seat back and inflate the airbag rearward and obliquely upward;
The airbag module is fastened to at least one of the bottom wall and the side wall . A headrest is provided on an upper portion of the seat back,
The headrest includes a headrest body and a pair of left and right pillars protruding from the headrest body,
2. The vehicle seat according to claim 1, wherein the pillar is coupled to the seat back frame at a position forward of a rear end of the bracket. A headrest is provided on an upper portion of the seat back,
The headrest includes a headrest body and a pair of left and right pillars protruding from the headrest body,
The vehicle seat according to claim 1 , wherein the pillar is joined to the seat back at a position where the pillar overlaps with the recess in the vertical direction. A headrest is provided on an upper portion of the seat back,
The headrest includes a headrest body and a pair of left and right pillars protruding from the headrest body,
The airbag module is fastened to the bracket by a fastening member,
The vehicle seat according to claim 1 , wherein the pillar is joined to the seat back at a position where the pillar vertically overlaps with the fastening member. 2. The vehicle seat according to claim 1, wherein the bracket is coupled to the corresponding side frame at left and right edges. 6. The vehicle seat according to claim 5, wherein the bracket is made of a single plate member integrally provided with a pair of left and right lower tongue pieces extending laterally from the left and right edges. The vehicle seat according to any one of claims 1 to 6, wherein the recess overlaps with the side frame in a side view. the airbag module houses the airbag and the inflator, and
The device includes a retainer that opens rearward and a cover that closes the opening of the retainer.
8. The vehicle seat according to claim 1, wherein the inflator is fixed to a lower half of the retainer. A through hole is formed in a lower portion of the bottom wall of the recess,
The airbag module is fastened to the bottom of the recess by a fastener passing through the through hole.
Fastened to the wall,
The vehicle seat according to any one of claims 1 to 8, wherein the inflator is positioned rearward of the fastener. The seat back has a pad member supported by the seat back frame,
The vehicle seat according to any one of claims 1 to 9, wherein at least a portion of the cover member is disposed along a surface of the pad member.

Images