Vehicle seat

A vehicle seat including: a back frame that forms a framework of a seat back; a back pad including a cushion material attached to a seated person side of the back frame; a back cover that covers a seated person side of the back pad; and an airbag unit that is attached to the back frame, the airbag unit including an airbag, wherein a break portion that allows the airbag to expand and deploy is formed to the back cover, wherein a fabric member that is difficult to stretch than the back cover is disposed between the break portion and the back frame, and wherein a buffer member that prevents damage due to abutment is attached to a portion of the fabric member which may abut with a part of the back frame in a process in which the airbag is expanded and deployed.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based upon and claims the benefit of priority from prior Japanese patent application No. 2021-029788, filed on Feb. 26, 2021, the entire contents of which are incorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates to a vehicle seat.

BACKGROUND ART

In related art, there is known a vehicle seat of a vehicle in which an airbag unit is disposed inside a seat back, and when an impact load is applied to the vehicle from a side of the vehicle, an airbag of the airbag unit is expanded and deployed to an outside of the seat back to protect a body of a seated occupant. JP-A-2017-121869 discloses this type of vehicle seat, in which the airbag unit is disposed on a back side of a back pad, and the back pad on a front side of the airbag unit is provided with a through hole serving as an expansion path of the airbag. A back cover that covers the back pad of such vehicle seat is provided in a tensioned state, and a sewn line portion that is broken by the expansion and deployment of the airbag is disposed along the through hole. In the vicinity of the sewn line portion, a stay cloth, which is a low-stretch cloth having a function of preventing stretching of the back cover in an initial stage of the expansion and deployment of the airbag so as to reliably open the sewn line portion, is sewn.

In the technique described in JP-A-2017-121869, the airbag unit is attached to a seated person side of a back pan made of a resin plate which is attached to the seated person side of a metal back frame. A pair of stay clothes are disposed around the airbag unit so as to connect between the sewn line portion of the back cover and a bracket fixing the airbag unit to the back pan. Here, when the airbag is expanded and deployed, the stay clothes do not come into contact with metal parts such as a back frame. However, there is a possibility that a part of the stay clothes may come into contact with the back frame when the airbag is expanded and deployed, for example, in a case where one end portion side of the stay cloth is directly attached to the back frame. In such a case, if the back frame includes a sharp edge portion, there is a problem that when the airbag is expanded and deployed, the stay clothes may be damaged by the sharp edge portion, and the function of the stay clothes may not be sufficiently exerted.

SUMMARY

The present disclosure provides a vehicle seat in which a stay cloth that promotes opening of a sewn line portion of a back cover at a time of expansion and deployment of an airbag is prevented from coming into contact with a sharp edge portion of a back frame and being damaged.

According to an aspect of the present disclosure, there is provided a vehicle seat including: a back frame that forms a framework of a seat back; a back pad including a cushion material attached to a seated person side of the back frame; a back cover that covers a seated person side of the back pad; and an airbag unit that is attached to the back frame, the airbag unit including an airbag, wherein a break portion that allows the airbag to expand and deploy is formed to the back cover, wherein a fabric member that is difficult to stretch than the back cover is disposed between the break portion and the back frame, and wherein a buffer member that prevents damage due to abutment is attached to a portion of the fabric member which may abut with a part of the back frame in a process in which the airbag is expanded and deployed.

Accordingly, in the vehicle seat, even if a sharp edge or the like is present in a portion of the back frame with which the fabric member may abut in the process in which the airbag is expanded and deployed, the buffer member can reinforce the fabric member to avoid the damage to the fabric member. Accordingly, the break portion of the back cover can be reliably opened by an action of the fabric member to thereby expand and deploy the airbag. Further, since it is only necessary to attach the fabric member to which the buffer member is attached to the back frame, it is not necessary to attach other parts such as a protector to the back frame, and thus, assembling workability of the vehicle seat is good.

DESCRIPTION OF EMBODIMENTS

FIGS.1to7show an embodiment of the present disclosure. This embodiment is an example in which the present disclosure is applied to an automobile seat1. In the drawings, arrows indicate directions of an automobile and the automobile seat1when the automobile seat1is attached to the automobile. In the following description, description relating to the directions uses these directions as a reference. The automobile seat1of the present embodiment includes a seat cushion2serving as a seating portion, a seat back10serving as a backrest, and a headrest3that supports a head. Since the seat cushion2and the headrest3have a known configuration, the description thereof will be omitted, and the seat back10will be described. Here, the automobile seat1corresponds to the “vehicle seat” in the claims.

As shown inFIGS.1to4, the seat back10has a structure in which a back pad12made of urethane foam, which is a cushion material, is placed on a back frame11forming a framework thereof, and the back pad12is covered with a back cover13which is a covering material from above.

The back frame11is a member formed in a substantially rectangular frame shape in a front view by connecting upper portions of a pair of left and right side frames11a, which are pressed members having a substantially U-shaped cross section extending in a vertical direction, with an upper frame11bwhich is a pipe member, and connecting central portions of the pair of left and right side frames11ain the vertical direction with a center frame11cwhich is a pipe member. As shown inFIG.4, a horizontal cross section of the side frame11ahas a substantially U-shape that opens toward a left direction (seat inside direction), and includes a front surface portion11a1, a rear surface portion11a2, and a side surface portion11a3that connects a right end portion of the front surface portion11a1and a right end portion of the rear surface portion11a2in a front-rear direction. A left end portion side (opening side) of the front surface portion11a1is formed as a front end surface portion11a4which is bent in a rearward direction, and a left end portion side (opening side) of the rear surface portion11a2is formed as a rear end surface portion11a5which is bent in a forward direction. The front surface portion11a1is formed to have a shorter length in a left-right direction than the rear surface portion11a2. An airbag unit14is attached to a right side surface (seat outer surface) slightly above the central portion in the vertical direction of the right side frame11avia a bracket11d. Lower end portions of the pair of left and right side frames11aare connected to a rear end portion of a cushion frame (not shown) via a recliner (not shown), and an inclination of the back frame11with respect to the cushion frame can be adjusted. The airbag unit14includes an inflator14athat generates gas and an airbag14bthat is folded, and is attached to the side frame11aby fixing the inflator14ato the bracket11d.

As shown inFIGS.1,2, and4, the back pad12mainly includes a seating surface portion121having a seating surface of a concave shape on which a back of a seated person abuts, and a bank portion122supporting sides of the seated person. The bank portion122is located on both left and right outer sides of the seating surface portion121, and has a convex shape projecting forward from the seating surface portion121. The back pad12is attached to the back frame11in a state of being covered from the front with respect to the back frame11.

In a state where the back pad12is attached to the back frame11, a groove portion122arecessed forward is provided at a position on a back surface side of the bank portion122which faces a front surface of the airbag unit14. An opening portion122bis provided to the groove portion122aon a side of the airbag unit14. When gas is supplied from the inflator14a, the airbag14bcan be deployed by entering into the groove portion122afrom the opening portion122b, pushing and expanding the groove portion122a, and breaking the back pad12.

As shown inFIGS.1,2, and4, the back cover13is formed into a bag shape by sewing cut covering material parts. As the covering material, a planar member is used in which a surface cover13asuch as fabric or leather disposed on a seated person side, a urethane slab pad13b, and a back base cloth13cmade of cotton cloth or nonwoven fabric are stacked in this order and laminated (seeFIG.7). InFIG.4, the covering material having the three-layer structure is represented by a single solid line. There are three types of covering material parts which are: (1) a main cover portion131corresponding to the seating surface portion121of the back pad12; (2) a side cover portion132corresponding to a seating surface side of the bank portion122of the back pad12; and (3) a rear cover portion133covering a side portion of the bank portion122of the back pad12and a rear portion of the back pad12. Only the side cover portion132is prepared in a pair on left and right sides.

As shown inFIGS.1,2, and4, the main cover portion131and the left and right side cover portions132are sewn together by a sewing line S1, and the left and right side cover portions132and the rear cover portion133are sewn together by a sewing line S2. The sewing line S1is drawn in the hanging groove portion123which is provided between the seating surface portion121and the bank portion122of the back pad12and is recessed toward the rear side, and is hanged and fixed. A method of hanging and fixing is a known method of locking a wire attached to a hanging cotton cloth integrally sewn by the sewing line S1to a wire inserted in the back pad12by a hog ring or the like, and detailed description thereof will be omitted.

A part of the sewing line S2is disposed at a position close to the groove portion122aof the back pad12corresponding to the front of a position where the airbag unit14is disposed. In the part of the sewing line S2, one end portion of a belt-shaped inner side stay cloth15disposed on a seat inner side and one end portion of a belt-shaped outer side stay cloth16disposed on a seat outer side are integrally sewn to the back cover13. As shown inFIGS.5and6, the inner side stay cloth15includes a belt-shaped main body portion15ahaving a substantially rectangular development shape, and a rectangular flat plate-shaped buffer portion15battached to a part of the main body portion15aby sewing. The main body portion15ais formed of a fabric that is difficult to stretch than the covering material of the back cover13such as a nylon woven fabric. The buffer portion15bis formed of a felt material or a material obtained by laminating a resin film on the felt material. One end portion side15alof the main body portion15ain a longitudinal direction is a portion attached to the back cover13by the sewing line S2, and a hook member15cmade of resin is attached to the other end portion side15a2of the main body portion15ain the longitudinal direction by sewing on a surface on the same side as the surface to which the buffer portion15bis attached. The inner side stay cloth15is attached to the back cover13by the sewing line S2in a state in which the surface of the main body portion15aon the side to which the buffer portion15bis attached abuts with a surface of the side cover portion132on a side of the back base cloth13c. As shown inFIGS.1,3, and4, the outer side stay cloth16is a belt-shaped member having a substantially rectangular development shape, and is formed of the same material as that of the main body portion15aof the inner side stay cloth15. One end portion side16aof the outer side stay cloth16in the longitudinal direction is a portion attached to the back cover13by the sewing line S2, and a hook member16cmade of resin is attached to another end portion side16bof the outer side stay cloth16in the longitudinal direction by sewing. Here, the main body portion15aand the buffer portion15bcorrespond to the “fabric member” and the “buffer member” in the claims, respectively.

As shown inFIGS.1,2, and4, a stay cloth fixing member17is disposed on the rear end surface portion11a5of a portion of the right side frame11ato which the airbag unit14is attached. The stay cloth fixing member17is a resin component that has a constant transverse section and extends in the vertical direction, and includes a groove-shaped frame attaching portion17athat opens in a rear right direction, a groove-shaped inner side stay cloth attaching portion17bthat opens in a rear left direction, and a groove-shaped outer side stay cloth attaching portion17cthat opens in a front right direction. In the stay cloth fixing member17, in a state where the frame attaching portion17ais fitted and fixed to the rear end surface portion11a5of the side frame11a, the hook member15cof the inner side stay cloth15is locked and fixed to the inner side stay cloth attaching portion17b, and the hook member16cof the outer side stay cloth16is locked and fixed to the outer side stay cloth attaching portion17c.

As shown inFIG.4, the back pad12is fixed to the back frame11in a state where the back pad12covers the back frame11from the front, and the back cover13is covered thereon. Then, the inner side stay cloth15is disposed between the seating surface side of the bank portion122of the back pad12and the back base cloth13cside of the side cover portion132of the back cover13, the other end portion side15a2is passed through the through hole in the hanging groove portion123toward the rear, and the hook member15cis locked and fixed to the inner side stay cloth attaching portion17b. At this time, the buffer portion15bof the inner side stay cloth15is disposed to face a left end portion of the front end surface portion11a4of the right side frame11a, and the main body portion15aof the inner side stay cloth15does not come into direct contact with the left end portion of the front end surface portion11a4. Further, the outer side stay cloth16is disposed between a right surface side (side surface side) of the bank portion122of the back pad12and the back base cloth13cside of the rear cover portion133of the back cover13, and the hook member16cis locked and fixed to the outer side stay cloth attaching portion17c. In this state, the airbag unit14is wound by the inner side stay cloth15and the outer side stay cloth16via the back pad12.

The present embodiment configured as described above has the following advantageous effects. In a state as shown inFIG.4, when an impact load is applied to the automobile from the side of the automobile, the inflator14aof the airbag unit14is activated to generate gas, and the airbag14bstarts to expand and deploy by the gas. The airbag14bthat expands and deploys enters into the groove portion122aof the back pad12from the opening portion122b, pushes and expands the groove portion122a, and breaks the back pad12. Further, the airbag14bthat expands and deploys pushes the back cover13forward, and the sewing line S2begins to break. Specifically, the one end portion side15alof the inner side stay cloth15and the one end portion side16aof the outer side stay cloth16are integrated by sewing by a part of the sewing line S2, and since the inner side stay cloth15and the outer side stay cloth16are difficult to stretch than the back cover13, stress is concentrated on a portion where the inner side stay cloth15and the outer side stay cloth16are sewn, and breakage starts from here. At this time, the inner side stay cloth15is stretched and a part of the inner side stay cloth15abuts against the left end portion of the front end surface portion11a4of the right side frame11a, but since the buffer portion15bis disposed in this portion, the main body portion15aof the inner side stay cloth15does not come into direct contact with the left end portion of the front end surface portion11a4. Accordingly, even if a sharp edge or the like is present at the left end portion of the front end surface portion11a4, damage to the main body portion15acan be avoided by the buffer portion15binterposed between the main body portion15aand the left end portion of the front end surface portion11a4, and the sewing line S2can be reliably opened by an action of the main body portion15ato thereby expand and deploy the airbag14bto the outside of a seat. Further, since it is only necessary to attach the hook member15cmade of resin that is attached to the other end portion side15a2of the inner side stay cloth15to the stay cloth fixing member17attached to the right side frame11a, it is not necessary to attach other parts such as a protector to the side frame11a, and thus, assembling workability of the automobile seat1is good.

Further, since the buffer portion15bis attached to the surface of the main body portion15aon a side of the right side frame11a, when the inner side stay cloth15abuts with the left end portion of the front end surface portion11a4, the main body portion15acan be made less likely to be damaged. Further, since the buffer portion15bis a flexible flat plate-shaped felt material, the buffer portion15bcan be easily attached to the main body portion15aby means of sewing or the like.

Although specific embodiments have been described above, the present disclosure is not limited to the appearance and configuration thereof, and various modifications, additions, and deletions may be made without departing from the scope of the present disclosure. Examples thereof include the following.

1. In the above embodiment, the buffer portion15bis formed of a felt material or a material obtained by laminating a resin film on the felt material. However, the present disclosure is not limited thereto, and a resin sheet, a thick fabric, or the like may be used as long as the main body portion15acan be prevented from being damaged.

2. In the above embodiment, the buffer portion15bis disposed on the side of the main body portion15awhich faces the left end portion of the front end surface portion11a4of the right side frame11a. However, regardless of the above, although an effect of buffering is slightly inferior, the buffer portion15bcan be disposed on a side opposite to the side of the main body portion15awhich faces the left end portion of the front end surface portion11a4of the right side frame11a.

3. In the above embodiment, the sewing line S2is set as a break portion, but the present disclosure is not limited thereto. A general portion of the back cover13can be weakened to form the break portion.

4. In the above embodiment, the present disclosure is applied to the automobile seat, but the present disclosure is not limited thereto. The present disclosure can also be applied to seats of a railway vehicle, a ship, an aircraft, and the like.

The disclosure provides illustrative, non-limiting examples as follows:

According to a first aspect, there is provided a vehicle seat including: a back frame that forms a framework of a seat back; a back pad including a cushion material attached to a seated person side of the back frame; a back cover that covers a seated person side of the back pad; and an airbag unit that is attached to the back frame, the airbag unit including an airbag, wherein a break portion that allows the airbag to expand and deploy is formed to the back cover, wherein a fabric member that is difficult to stretch than the back cover is disposed between the break portion and the back frame, and wherein a buffer member that prevents damage due to abutment is attached to a portion of the fabric member which may abut with a part of the back frame in a process in which the airbag is expanded and deployed.

According to the first aspect, in the vehicle seat, even if a sharp edge or the like is present in a portion of the back frame with which the fabric member may abut in the process in which the airbag is expanded and deployed, the buffer member can reinforce the fabric member to avoid the damage to the fabric member. Accordingly, the break portion of the back cover can be reliably opened by an action of the fabric member to thereby expand and deploy the airbag. Further, since it is only necessary to attach the fabric member to which the buffer member is attached to the back frame, it is not necessary to attach other parts such as a protector to the back frame, and thus, assembling workability of the vehicle seat is good.

According to a second aspect, there is provided the vehicle seat according to the first aspect, wherein the buffer member is attached to a surface of the fabric member on a back frame side

According to the second aspect, in the vehicle seat, since the buffer member is attached to the surface of the fabric member on the back frame side, it is possible to prevent the back frame from directly abutting with the fabric member and to make the fabric member less likely to be damaged.

According to a third aspect, there is provided the vehicle seat according to the first or second aspect, wherein the buffer member is a flexible flat plate-shaped felt material.

According to the third aspect, in the vehicle seat, since the buffer member is the flexible flat plate-shaped felt material, the buffer member can be easily attached to the fabric member by sewing or the like.

According to a fourth aspect, there is provided the vehicle seat according to any one of the first to third aspects, wherein the break portion includes a sewing line.

According to a fifth aspect, there is provided the vehicle seat according to the fourth aspect, wherein the back cover and one end portion of the fabric member are sewn together by the sewing line.

According to a sixth aspect, there is provided the vehicle seat according to any one of the first to fifth aspects, wherein the back frame includes an edge portion, and wherein the buffer member faces the edge portion of the back frame.