Conveyance seat

Provided is a conveyance seat that effectively reduces a load to be applied to an occupant at the time of a vehicle collision. A conveyance seat includes a seat back and a headrest. The seat back includes a chest support member inside the seat back, which receives a chest of an occupant to support the chest of the occupant when a backward movement load is applied to the occupant because of a vehicle collision. The headrest includes a head support member inside the headrest, which receives a head of the occupant to support the head of the occupant when the backward movement load is applied to the occupant. When the backward movement load is applied to the occupant, both the chest support member and the head support member receive the backward movement load.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is the U.S. National Stage entry of International Application No. PCT/JP2020/012260 filed under the Patent Cooperation Treaty and having a filing date of Mar. 19, 2020, which claims priority to Japanese Patent Application No. 2019-055602 having a filing date of Mar. 22, 2019, Japanese Patent Application No. 2019-055603 having a filing date of Mar. 22, 2019, and Japanese Patent Application No. 2019-086748 having a filing date of Apr. 26, 2019, all of which are incorporated herein by reference.

TECHNICAL FIELD

The present invention relates to a conveyance seat to be mounted in a vehicle, particularly to a conveyance seat that reduces a load to be applied at the time of a vehicle collision.

BACKGROUND ART

A conveyance seat has been provided with a countermeasure for a phenomenon in which an occupant moves backward to sink into a seat at the time of a vehicle collision (hereinafter, sinking phenomenon). For example, a technology depicted in PATENT LITERATURE 1 is disclosed as a countermeasure to reduce a load to be applied to an occupant who is a seated occupant when the sinking phenomenon occurs.

CITATION LIST

Patent Literature

PATENT LITERATURE 1: JP 2017-222363 A

SUMMARY OF INVENTION

Technical Problem

When the sinking phenomenon occurs, the sinking amount of a chest of the seated occupant is larger than the sinking amount of a neck, a lumbar, or the like. Because of a difference in sinking amount described above, the posture of the occupant is in a stooped state, and a forward load is applied to the occupant as a reaction force from the seat.

Therefore, the present invention has been made in view of the above problem, and an object of the present invention is to provide a technique in which when a sinking phenomenon occurs at the time of a vehicle collision, a cervical spine also moves in a well-balanced manner according to a movement of a thoracic spine to reduce the sinking amount of a chest, and to reduce a difference between the sinking amount of the chest and the sinking amount of a head, thereby suppressing a sense of discomfort of an occupant.

Solution to Problem

In order to solve the above problem, there is provided a conveyance seat including a seat back. The seat back includes a seat back frame, and a chest support member that is provided in an upper portion of the seat back frame, and that receives a chest of an occupant to reduce a backward movement load while moving backward with respect to the seat back frame, and to support the chest of the occupant when the backward movement load is applied to the occupant because of a vehicle collision. The chest support member is provided at a position to overlap the upper portion of the seat back frame in a height direction.

Since the conveyance seat of the present invention configured as described above includes the chest support member provided in the upper portion of the seat back frame to support the chest of the occupant, when a sinking phenomenon occurs, the sinking amount of the chest is reduced, and a difference between the sinking amount of the chest and the sinking amount of a head is reduced. Therefore, the load to be applied to the occupant at the time of a vehicle collision can be effectively reduced.

In addition, it is preferable that the conveyance seat further includes a headrest provided above the seat back; and a headrest guide provided at an upper end of the seat back frame to support the headrest, and that the chest support plate is provided to be connected to the headrest guide.

Since the chest support plate is provided at a position to overlap the headrest guide in a height direction, the difference between the sinking amount of the chest and the sinking amount of the head can be further reduced.

In addition, in the conveyance seat, it is more preferable that the chest support member is formed along an extending direction of a front surface of a headrest pillar when seen from a side surface of the conveyance seat.

In the above configuration, the occupant comes into contact with the headrest pillar and the chest support member substantially simultaneously at the time of a vehicle collision. Therefore, the difference between the sinking amount of the chest and the sinking amount of the head can be further reduced.

In addition, in the conveyance seat, it is more preferable that the chest support member is provided at a position to overlap an upper pipe of the seat back frame in the height direction.

Since the chest support member is provided at a position to overlap the upper pipe in the height direction, the positions of the headrest and the chest support member are very close to each other, so that the difference between the sinking amount of the chest and the sinking amount of the head can be further reduced.

In addition, in the conveyance seat, it is preferable that the seat back includes a pressure receiving portion provided in a side frame of the seat back frame to support the occupant from behind, and that the chest support member is provided to be located above the pressure receiving portion.

Since the chest support member is located above the pressure receiving portion, the difference between the sinking amount of the chest and the sinking amount of the head can be further reduced.

In addition, in the conveyance seat, it is preferable that the chest support member includes a first deformable member provided at an upper end of the chest support member to be connected to the seat back frame.

Since the first deformable member is provided at the upper end of the chest support member to be connected to the seat back frame, when a backward movement load is applied, the first deformable member is deformed, so that the backward movement load can be reduced more appropriately.

In addition, in the conveyance seat, it is more preferable that the chest support member is connected and fixed to a side portion of the seat back frame via a second deformable member.

Since the chest support member and the side portion of the seat back frame are connected to each other via the second deformable member, the movement amount of the chest support member at the time of application of a backward movement load is adjustable, and the backward movement load can be reduced more appropriately.

In addition, in order to solve the above problem, the conveyance seat further includes a headrest. The headrest includes a head support member inside the headrest, which receives a head of the occupant to turn backward, and to support the head of the occupant when the backward movement load is applied to the occupant. When the backward movement load is applied to the occupant, both the chest support member and the head support member receive the backward movement load.

In the conveyance seat of the present invention configured as described above, both the chest support member that supports the chest, and the head support member that supports the head receive the backward movement load, so that a cervical spine also moves in a well-balanced manner according to a movement of the thoracic spine. As a result, the sinking amount of the chest is reduced, and the difference between the sinking amount of the chest and the sinking amount of the head is reduced. Therefore, a sense of discomfort of the occupant can be suppressed.

In addition, in the conveyance seat, it is preferable that the chest support member and the head support member are provided in the seat back and the headrest, respectively, such that the chest support member moves backward first and the head support member turns backward next when the backward movement load is applied to the occupant.

In addition, in the conveyance seat, it is preferable that the head support member includes a neck support portion that receives a neck of the occupant to support the neck of the occupant when the backward movement load is applied to the occupant.

Since the head support member includes the neck support portion that supports the neck of the occupant, the head support member allows the neck of the occupant to move backward while supporting the neck.

In addition, in the conveyance seat, it is preferable that in the head support member, a portion facing the head of the occupant is formed in a recessed shape to be recessed backward, and a portion facing a neck of the occupant is formed in a protruding shape to protrude forward.

In addition, in the conveyance seat, it is more preferable that the chest support member has a chest contact surface that comes into contact with the chest of the occupant, that the head support member has a head contact surface that comes into contact with the head of the occupant, and that a lower end of the head contact surface is located on an extension of the chest contact surface when the conveyance seat is seen from a side.

Since the lower end of the head contact surface is located on the extension of the chest contact surface, the head contact surface and the chest contact surface are disposed on a straight line to facilitate receiving the occupant.

In addition, in the conveyance seat, it is more preferable that the chest support member and the head support member are disposed to align a center of the chest support member in a width direction with a center of the head support member in the width direction.

Since the chest support member and the head support member are disposed to align the centers thereof with each other, a spine of the occupant, particularly the thoracic spine can be supported in a state where the thoracic spine is received more reliably.

In addition, in the conveyance seat, it is more preferable that a length of the chest support member in a width direction is larger than a length of the head support member in the width direction.

Since the length of the chest support member in the width direction is set large, the chest of the occupant can be received and supported more reliably.

In addition, in the conveyance seat, it is more preferable that a storage portion that stores the chest support member is provided in a pad back surface of the seat back.

Since the storage portion that stores the chest support member is provided in the pad back surface of the seat back, the position of the chest support member is stable, for example, during normal use.

In addition, in the conveyance seat, it is preferable that when the backward movement load is applied to the occupant to move the chest support member backward, a lower portion of the chest support member is deformed before an upper portion of the chest support member is deformed.

Since the lower portion of the chest support member is deformed before the upper portion of the chest support member is deformed, the difference between the sinking amount of the chest and the sinking amount of the head can be further reduced.

In addition, in the conveyance seat, it is preferable that when the backward movement load is applied to the occupant to move the chest support member backward, a movement amount of the upper portion of the chest support member is larger than a movement amount of the lower portion of the chest support member.

When the backward movement load is applied, the movement amount of the headrest that supports the head of the occupant is increased since a rotation axis of the seat back is present on a lower side of the seat back. For that reason, when the movement amount of the upper portion of the chest support member is set to be larger than the movement amount of the lower portion of the chest support member, the difference between the sinking amount of the chest and the sinking amount of the head can be reduced.

In addition, in the conveyance seat, it is preferable that the first deformable member has a hinge structure.

Since the first deformable member has a hinge structure, the backward movement load can be reduced more appropriately.

In addition, in the conveyance seat, it is more preferable that the chest support member and the head support member are provided in the seat back and the headrest, respectively, such that the head support member turns backward while the chest support member moves backward, and thus both the chest support member and the head support member receive the backward movement load.

In addition, in the conveyance seat, it is more preferable that when the backward movement load is applied to the occupant, a movement amount of the chest support member is larger than a movement amount of the head support member.

Since the movement amount of the chest support member at the time of application of the backward movement load is set large, a load on the chest can be reduced in a state where the spine shape is maintained.

Advantageous Effects of Invention

According to the present invention, since the chest support member is provided at a position to overlap the upper portion of the seat back frame in the height direction, when a sinking phenomenon occurs at the time of a vehicle collision, the sinking amount of the chest is reduced, and the difference between the sinking amount of the chest and the sinking amount of the head is reduced. Therefore, a load to be applied to the occupant at the time of the vehicle collision can be effectively reduced.

In addition, since the chest support member is provided at a position to overlap the headrest guide in the height direction, the difference between the sinking amount of the chest and the sinking amount of the head can be further reduced.

In addition, in a case where the chest support member is formed along the extending direction of the front surface of the headrest pillar when seen from the side surface of the conveyance seat, the occupant comes into contact with the headrest pillar and the chest support member substantially simultaneously at the time of a vehicle collision. Therefore, the difference between the sinking amount of the chest and the sinking amount of the head can be further reduced.

In addition, since the chest support member is provided at a position to overlap the upper pipe in the height direction, the positions of the headrest and the chest support member are very close to each other, so that the difference between the sinking amount of the chest and the sinking amount of the head can be further reduced.

In addition, since the chest support member is located above the pressure receiving portion, the difference between the sinking amount of the chest and the sinking amount of the head can be further reduced.

Since the first deformable member is provided at the upper end of the chest support member to be connected to the seat back frame, when a backward movement load is applied, the first deformable member is deformed, so that the backward movement load can be reduced more appropriately.

Since the chest support member and the side portion of the seat back frame are connected to each other via the second deformable member, the movement amount of the chest support member at the time of application of a backward movement load is adjustable, and the backward movement load can be reduced more appropriately.

In addition, since the storage portion that stores the chest support member is provided in the pad back surface of the seat back, the position of the chest support member is stable, for example, during normal use.

In addition, according to the present invention, at the time of a vehicle collision, both the chest support member that supports the chest, and the head support member that supports the head receive a backward movement load of the occupant, so that the cervical spine also moves in a well-balanced manner according to a movement of the thoracic spine. Therefore, a sense of discomfort of the occupant can be suppressed.

At that time, the chest support member receives the load first, and the head support member receives the load next, so that the load is received according to a backward movement of the occupant. Therefore, a sense of discomfort of the occupant at the time of the vehicle collision can be further suppressed.

In addition, it is more effective when both the chest support member and the head support member simultaneously receive a load.

In addition, since the head support member includes the neck support portion that supports the neck of the occupant, the head support member allows the neck of the occupant to move backward while supporting the neck.

In addition, the portion facing the head of the occupant is formed in a recessed shape to be recessed backward, and the portion facing the neck of the occupant is formed in a protruding shape to protrude forward. Accordingly, the head and the neck of the occupant are stably supported.

Since the lower end of the head contact surface is located on the extension of the chest contact surface, the spine shape of the occupant and the shapes of the head contact surface and the chest contact surface are disposed on a straight line to facilitate receiving the occupant.

In addition, since the chest and the head contact surface are disposed to align the centers thereof with each other, the spine of the occupant, particularly the thoracic spine can be supported in a state where the thoracic spine is received more reliably.

Since the length of the chest support member in the width direction is set large, the chest of the occupant can be received and supported more reliably.

In addition, since the storage portion that stores the chest support member is provided in the pad back surface of the seat back, the position of the chest support member is stable, for example, during normal use.

In addition, since the lower portion of the chest support member is deformed before the upper portion of the chest support member is deformed, the difference between the sinking amount of the chest and the sinking amount of the head can be further reduced.

In addition, when the movement amount of the upper portion of the chest support member is set to be larger than the movement amount of the lower portion of the chest support member, the difference between the sinking amount of the chest and the sinking amount of the head can be reduced.

Since the first deformable member has a hinge structure, the backward movement load can be reduced more appropriately.

Since the movement amount of the chest support member at the time of application of the backward movement load is set large, a load on the chest can be reduced in a state where the spine shape is maintained.

DESCRIPTION OF EMBODIMENTS

Hereinafter, conveyance seats according to embodiments of the present invention (hereinafter, the present embodiment) will be described with reference toFIGS.1to18.

Incidentally, the embodiments to be described below are merely one example to facilitate understanding of the present invention, and do not limit the present invention. Namely, the shapes, dimensions, dispositions, and the like of members to be described below can be changed or improved without departing from the concept of the present invention, and it goes without saying that the present invention includes equivalents thereof. In addition, in the following embodiments, the same or similar components are denoted by common reference signs, and in order to facilitate understanding, the scales of the drawings are appropriately changed.

Incidentally, in the following description, as indicated by arrows inFIG.1, a front to back direction means a front to back direction when seen from an occupant seated in a conveyance seat, a width direction means a width direction (lateral width direction) of a seat back of the conveyance seat, and a height direction means a height direction of the seat back, strictly speaking, means an up to down direction of the seat back when the seat back is seen from the front. In addition, unless otherwise specified, the shape or disposition position of each member to be described later is a shape or disposition position in a seatable state of the conveyance seat.

First Embodiment

First, an entire configuration of a conveyance seat100including a seat frame101which is a first embodiment of the present invention will be described with reference toFIGS.1to7D.FIGS.1and2are views illustrating a structure example of the conveyance seat100and a seat frame SF,FIG.1is a perspective view illustrating an exterior shape of the conveyance seat100, andFIG.2is a perspective view illustrating an exterior shape of the seat frame101.FIGS.3and4are views illustrating a state where an occupant H is seated in the conveyance seat100, andFIG.5is a view illustrating a state where the occupant H is moved backward while being supported when a backward movement load is applied.FIGS.6A to6Care perspective views illustrating a first deformable member and other examples thereof, andFIGS.7A to7Dare perspective views illustrating a second deformable member and other examples thereof.

As illustrated inFIG.1, the conveyance seat100includes a seat back S1that supports a back (chest H3and the like) of the occupant H, a seat cushion S2that supports buttocks of the occupant H, and a headrest S3that supports a head H1of the occupant H. The above components are formed by placing pads1a,2a, and3aon frames as skeletons of the components and covering the pads1a,2a, and3awith skin materials1b,2b, and3b.

Here, as illustrated inFIG.2, in the seat frame101, a lower end portion of a seat back frame1forming the skeleton of the seat back S1is connected to a rear end portion of a seat cushion frame2forming the skeleton of the seat cushion S2. In addition, a reclining mechanism not illustrated intervenes between the seat back frame1and the seat cushion frame2. Accordingly, the seat back frame1is turnable around a reclining shaft11with respect to the seat cushion frame2, and the backward tilt angle (backrest angle) of the seat back S1with respect to the seat cushion S2is adjustable. Incidentally, the reclining shaft11penetrates through aside lower end portion of the seat back frame1and a side rear end portion of the seat cushion frame2to protrude slightly outward in the width direction.

In addition, a headrest guide17having a tubular shape is attached to an upper central portion of the seat back frame1. Then, a headrest pillar19extending from a lower end of the headrest S3is inserted into the headrest guide17to attach the headrest S3to the seat back S1.

Next, a configuration example of the seat back frame1will be described with reference toFIG.2.FIG.2is a perspective view illustrating an exterior shape of the seat back frame1according to the present embodiment, and the width direction and the height direction are indicated by arrows in the same drawings.

As illustrated inFIG.2, the seat back frame1is a substantially rectangular frame generally formed of a metal member, and includes, as main components, a pair of side frames15provided in both end portions in the width direction, an upper pipe16provided in an upper end portion in the height direction, and a lower frame bridging portion18provided in a lower end portion. Incidentally, in the present embodiment, the side frames15, the upper pipe16, and the lower frame bridging portion18are combined and integrated from a state where the side frames15, the upper pipe16, and the lower frame bridging portion18are separated from each other, to form the seat back frame1, but may be originally integrated and molded, namely, may be integrally molded of a resin material.

The pair of side frames15are separated from each other in a right to left direction to define a width of the seat back S1, and both the side frames15are disposed to extend in the up to down direction. As illustrated inFIG.2, in the pair of side frames15, an upper end portion of each of the side frames15is located slightly behind a lower end portion thereof in a state where the posture of the conveyance seat100is in a seatable posture. In addition, the lower end portion of each of the side frames is formed wider than the upper end portion in the front to back direction.

The upper pipe16connects the upper end portions of the pair of side frames15, and is formed in an inverted U-shape in a front view. The upper pipe16according to the present embodiment is formed by bending a steel pipe, and both end portions thereof are attached to the upper end portions of the side frames15. In addition, two headrest guides17(may also be called pillar support portions) described above are attached to a central portion of the upper pipe16at an interval from each other.

As illustrated inFIG.2, a chest support member20is provided in an upper portion of the seat back frame1. Then, as illustrated inFIG.5, when a backward movement load is applied to the occupant (seated occupant) because of a vehicle collision, the chest support member20receives the chest of the occupant to reduce the backward movement load while moving backward with respect to the seat back frame1, and to support the chest H3of the occupant H.

The chest support member20is a flat plate-shaped member, and as illustrated inFIG.2, a back surface (surface opposite a chest contact surface20a, namely, a back surface20c) of the chest support member20is fixed to the upper pipe16of the seat back frame1via a first deformable member41. The chest support member20is attachedly provided at a position to overlap the upper pipe16(upper portion of the seat back frame1) in the height direction. Namely, the chest support member20is provided such that an upper end20bof the chest support member20is located at substantially the same position as that of the upper pipe16. The first deformable member41is connected to the headrest guide17provided at an upper end of the seat back frame1. Then, the chest support member20is provided at a position to overlap the headrest guide17in the height direction. Namely, the chest support member20is installed such that the upper end20bis present within a height range of the headrest guide17(refer toFIG.3).

The chest support member20is formed along an extending direction of a front surface19aof the headrest S3when seen from a side surface of the conveyance seat100(refer toFIG.3).

In addition, a lower flange portion25is formed in a lower end portion of the chest support member20. The chest support member20is reinforced by the lower flange portion25, and the chest support member20is suppressed from being curved backward when the chest support member20receives a load from the chest of the occupant H. Incidentally, as illustrated inFIG.4, the chest support member20is provided in contact with a storage portion29(chest support member-storage portion) formed in a pad back surface of the seat back S1. Since the chest support member20is installed in the storage portion29that is formed in a recessed shape in the pad back surface to allow the chest support member20to be in contact therewith, the position of the chest support member20is stable during normal use.

As illustrated inFIG.2, the seat back frame1includes a pressure receiving portion40formed of an S-shaped spring. The pressure receiving portion40supports a lumbar of the occupant H from behind. The chest support member20is provided to be located above the pressure receiving portion40, and supports the chest H3of the occupant H.

As illustrated inFIG.2, the chest support member20, specifically, the back surface20cof the chest support member20and the headrest guide17are connected to each other by the first deformable member41. In the present embodiment, as illustrated inFIGS.2and6C, the first deformable member41is realized by using a plate spring. In addition, the chest support member20is connected to a side portion of the seat back frame1via a second deformable member44. The second deformable member44is realized by a coil spring. In addition, the first deformable member41has a hinge structure. For this reason, at the time of a vehicle collision, when a backward movement load is applied to the occupant H in a direction of arrow A inFIG.3, the first deformable member41and the second deformable member44are deformed, so that the chest support member20turns in a direction of arrow D as illustrated inFIG.5to reduce the backward movement load.

When the occupant H is moved backward (in the direction of arrow A inFIG.3) due to the backward movement load, a lower portion23of the chest support member20is deformed before an upper portion22of the chest support member20is deformed.

FIGS.3and4illustrate a state of the occupant H and the conveyance seat100before a vehicle collision. In addition,FIG.5illustrates a state of the occupant H and the conveyance seat100at the time of a vehicle collision. When a backward movement load is applied, the occupant H is moved backward, and the head H1and the chest H3of the occupant H sink into the headrest S3and the seat back S1, respectively. At that time, as illustrated inFIG.5, the chest H3comes into contact with the chest support member20, and the backward movement load is reduced, so that a backward movement amount of the chest H3is suppressed. Namely, the sinking amount of the chest H3is reduced, and a difference between the sinking amount of the chest H3and the sinking amount of the head H1is reduced. The posture of the occupant is maintained as usual, and the occupant is suppressed from stooping. Namely, a load to be applied to the occupant H at the time of a vehicle collision is effectively reduced.

When a backward movement load is applied to the occupant H to move the chest support member20backward, the movement amount of the upper portion22of the chest support member20is set to be larger than the movement amount of the lower portion23of the chest support member20. When the backward movement load is applied, the seat back S1is tilted around the reclining shaft11in a direction of arrow C inFIG.5, so that the movement amount of the upper portion22is larger than the movement amount of the lower portion23. Therefore, the occupant H is suppressed from stooping.

As illustrated inFIG.6A, the first deformable member41that connects the chest support member20and the seat back frame1includes bent portions41aand41bbent in the middle thereof. Therefore, the first deformable member41is elastically deformable, and the angle or amount of deformation of the chest support member20with respect to the seat back frame1is adjustable.

In addition, as in a first deformable member42illustrated inFIG.6B, a hole portion42amay be formed in the middle of the first deformable member42. In addition, as in a first deformable member43illustrated inFIG.6C, a cutout43amay be formed in the middle of the first deformable member43. The amount of deformation of the first deformable member42is adjustable by forming the hole portion42aor the cutout43a.

Incidentally, the first deformable member41,42, or43may be provided to connect a side portion of the chest support member20and the seat frame. The first deformable members41,42, and43are realized by plate springs, but similarly to the second deformable members44to47to be described later, may be realized by coil springs, dampers, or the like.

In addition, a coil spring illustrated inFIG.7Ais provided as the second deformable member44in the chest support member20and a connecting portion (side portion of the seat back frame1) between the upper pipe16and the side frame15. The second deformable member may be realized by a telescopic damper as in the second deformable member45illustrated inFIG.7B. In addition, as in the second deformable member46illustrated inFIG.7C, the second deformable member may be realized by a deformable bracket in which a plurality of holes46aare formed. The second deformable member may be realized by a turnable damper as in the second deformable member47illustrated inFIG.7D.

In addition, the second deformable members44to47may be realized by plate springs similarly to the first deformable members41to43.

Second Embodiment

A conveyance seat110that is a second embodiment of the present invention will be described with reference toFIGS.8to14B. Incidentally, since the seat exterior shape of the conveyance seat110is the same as that of the conveyance seat100illustrated inFIG.1, and the structure of the seat cushion frame2of a seat frame102is also the same as that of the seat cushion frame2illustrated inFIG.2, a description thereof will be omitted.

A seat back frame3of the conveyance seat110has substantially the same structure as that of the seat back frame1of the conveyance seat100of the first embodiment, and as illustrated inFIG.8, is a substantially rectangular frame generally formed of a metal member. The seat back frame3includes, as main components, the pair of side frames15provided in both end portions in the width direction, the upper pipe16provided in an upper end portion in the height direction, and the lower frame bridging portion18provided in a lower end portion. A configuration for fixing a chest support member120to the seat back frame3is different.

The chest support member120is a flat plate-shaped member, and as illustrated inFIG.8, an upper flange portion124and a lower flange portion125are provided in an upper end portion and a lower end portion of the chest support member120, respectively. The chest support member120is reinforced by the upper flange portion124and the lower flange portion125, and the chest support member120is suppressed from being curved when a load is applied. In addition, the chest support member120is connected to the side frame15by a second deformable member144.

As illustrated inFIG.10A, the upper flange portion124of the chest support member120and the upper pipe16are connected to each other by a first deformable member141. The first deformable member141is a plate spring, and a deformable portion141ahaving a V-shaped cross section is formed in the vicinity of a center of the first deformable member141. The first deformable member141is joined to the upper pipe16by forming a welding portion55on a rear end portion of the first deformable member141and the upper pipe16and welding the welding portion55thereto. A front end portion of the first deformable member141is joined to the upper flange portion124of the chest support member120.

As illustrated inFIG.10A, the chest support member120is supported by the first deformable member141described above and a lock member50extending from the upper pipe16. The lock member50is a member having a cross section formed in an L-shape, and a rear end portion of the lock member50is fixed to the upper pipe such that the lock member50is turnable by a rotary shaft56. A front end portion of the lock member50is locked to a protrusion52provided on a back surface120cof the chest support member120during normal use. In addition, the front end portion of the lock member50is connected to the upper flange portion124of the chest support member120by a spring member51, and during normal use, the lock member50is pulled by the spring member51. The lock member50may be made of metal or resin.

Then, as illustrated inFIG.10B, when a backward movement load is applied in a direction of arrow E at the time of a vehicle collision, the front end portion of the lock member50disengages from the protrusion52, and the lock member50turns downward (in a direction of arrow F). When the support of the lock member50is removed, the deformable portion141ahaving a V-shaped cross section is pressed and crushed to deform the first deformable member141. The deformable portion141ais crushed to absorb an impact. At this time, the front end portion of the lock member50does not rotate since the front end is connected to the spring member51that is extended.

As illustrated inFIG.11, the deformable portion141aof the first deformable member141may include a linear portion141bformed flat in the middle of the deformable portion141a. The amount of deformation when a load is received may be adjusted by forming a hole or cutout in the linear portion141b.

FIGS.12A and12Billustrate a first deformable member142that is a modification example of the first deformable member141. Similarly to the first deformable member141, a rear end portion of the first deformable member142is connected to the upper pipe16by the welding portion55. A front end portion of the first deformable member142is also connected to the upper flange portion24of the chest support member120. A slit57extending backward from a tip of the front end portion is formed, and a fragile portion54formed of a thin plate is formed inside the slit57. The slit57and the fragile portion54form a deformable portion142a. The chest support member120includes a pin53that extends downward from the upper flange portion124to penetrate through the fragile portion54. The pin53is slidable inside the slit57. At the time of a vehicle collision, when a backward movement load is applied, the pin53slides to crush the fragile portion54, thereby absorbing an impact.

In the example illustrated inFIG.8, the second deformable member144of the chest support member120is connected to the side frame15of the seat back frame1; however, this configuration is one example, and the second deformable member144may be connected to the upper pipe16of the seat back frame1.

For example, as illustrated inFIG.13A, a second deformable member144amay be connected to an inner side portion of the upper pipe16by a connecting portion48a. In addition, as illustrated inFIG.13B, a second deformable member144bmay be connected to a rear portion of the upper pipe16by a connecting portion48b. The connecting portions48aand48bare fragile portions (second fragile portions), and are realized by welding or bonding using an adhesive. Since the chest support member120is connected to the seat back frame1by the fragile portion, the chest support member120is disengageable from the seat back frame1depending on the magnitude of a backward movement load applied to the occupant.

Namely, even when the second deformable member144aor144bis deformed, in a case where the backward movement load cannot be sufficiently reduced, the connecting portion48aor48bdisengages to reduce an impact. The application of a reaction force from the chest support member120to the occupant H is suppressed because of disengagement, and the chest of the occupant H can be protected.

In addition, when a hole, a cut, or the like is formed in the second deformable member144aor144bto provide a fragile portion (first fragile portion), and a backward movement load is applied, the fragile portion may break to cause the chest support member120to disengage from the seat back frame1.

The second deformable member144and a rear side of the side frame15may be connected to each other by a connecting portion48.

FIGS.14A and14Billustrate an example of a headrest S4attached to the seat back frame1so as to be rotatable backward.

The headrest S4is supported by a headrest pillar119. The headrest pillar119is held by a headrest guide117. A headrest guide stay118is attached to the upper pipe16of the seat back frame1so as to be rotatable backward (in a direction of arrow J inFIG.14B). The headrest guide stay118holds the headrest guide117and the headrest pillar119, and when the headrest guide stay118rotates backward, the headrest guide117and the headrest pillar119rotate backward. When the headrest pillar119rotates backward, the headrest S4also rotates, and as illustrated inFIG.14B, the headrest S4is stored backward. Hereinafter, a state of the headrest S4illustrated inFIG.14Ais called a first state (use state), and a state of the headrest S4illustrated inFIG.14Bis called a second state (stored state).

Incidentally, the headrest guide stay118is made of metal, and the headrest guide117is made of resin. The headrest pillar119is provided with a plurality of cutouts for the adjustment of height, and a claw portion provided in the headrest guide117engages with the cutout to lock the position of the headrest pillar119.

Since the headrest S4is rotatably attached, when the headrest S4is rotated to be in the stored state, for example, during autonomous driving, an occupant seated in a front seat (front seat occupant) and an occupant seated in a rear seat (rear seat occupant) easily talk to each other.

Incidentally, in the examples illustrated inFIGS.14A and14B, the headrest S4that is rotatable backward is illustrated; however, this configuration is one example, and for example, the headrest S4may be provided to be movable in the up to down direction by providing the seat back frame1with a general guide member.

In addition, the headrest S4may be attached to be movable in a horizontal direction or in the up to down direction by providing the seat back frame1with a link mechanism in which a plurality of links are combined, and providing the headrest S4at a tip of the link mechanism.

In addition, a biasing member such as a spring may be used, or an actuator formed of a drive member such as a motor may be used as means for moving the headrest S4. The headrest S4may be moved by air (fluid bag) using an air pump. In addition, an airbag may be applied.

In any method, when the vehicle is provided with a sensor that detects a collision of the vehicle before the vehicle collides, it is desirable that in order to protect the head of the occupant, when a collision is predicted, the headrest S4is set to be moved into the use state.

Third Embodiment

A conveyance seat200including the seat back frame1which is a third embodiment of the present invention will be described with reference toFIGS.15to18. Incidentally, since the seat exterior shape of the conveyance seat200is the same as that of the conveyance seat100illustrated inFIG.1, and the structures of the seat back frame1and the seat cushion frame2of a seat frame201are also the same as those of the seat back frame1and the seat cushion frame2illustrated inFIG.2, a description thereof will be omitted.

The conveyance seat200includes a head support member30inside the headrest S3. As illustrated inFIG.15, the head support member30is a member having a cross section formed in an S-shape. The head support member30of the headrest S3is provided to receive the head H1of the occupant H, and to support the head H1when a backward movement load is applied to the occupant H. The head support member30moves the chest H3and the head H1of the occupant H in cooperation with the chest support member20in a state where the spine shape of the occupant H is maintained.

In order to maintain the spine shape of the occupant H, the headrest S3is attached to the seat back S1so as to be turnable around a rotation axis32. When the headrest S3supports the head H1of the occupant H, the headrest S3supports the head H1while turning backward (in the direction of arrow C). When the headrest turns, the head support member30also turns, and a lower side (neck support portion31) of the head support member30comes into contact with a neck H2of the occupant to support the neck.

The chest support member20has the chest contact surface20athat comes into contact with a back side of the chest H3of the occupant H, and the head support member30has a head contact surface30athat comes into contact with the head H1of the occupant H. As illustrated inFIG.17, a lower end of the head contact surface30ais provided to be located on an extension of the chest contact surface20aaccording to the shape of a spine B (a cervical spine B1, a thoracic spine B2, and a lumbar spine B3(refer toFIG.3)) of the occupant H when the conveyance seat200is seen from the side. Since such disposition is employed, in a state where the spine shape of the occupant H is maintained, namely, in a state where the occupant H is not stooped, the chest support member20and the head support member30are capable of supporting the spine B of the occupant H, particularly, the cervical spine B1and the thoracic spine B2.

In addition, as illustrated inFIG.16, the chest support member20and the head support member30are disposed to align a center of the chest support member20in the width direction with a center G of the head support member30in the width direction. Since the chest support member20and the head support member30are disposed to align the centers G thereof with each other, the thoracic spine B2of the occupant H can be received more reliably and supported in a state where the spine shape is maintained.

In addition, as illustrated inFIG.16, a length L1of the chest support member20in the width direction is larger than a length L2of the head support member30in the width direction. Since the length L1of the chest support member20in the width direction is lengthened, the chest H3of the occupant H is received and supported more reliably. Therefore, the sinking amount of the chest H3is smaller than the sinking amount of the head H1, and the difference between the sinking amount of the chest H3and the sinking amount of the head H1is reduced.

In addition, as illustrated inFIGS.17and18, in the conveyance seat200of the present embodiment, when a backward movement load is applied to the occupant H, the movement amount of the chest support member20is set to be larger than the movement amount of the head support member30. Since the movement amount of the chest support member20is set large, the sinking amount of the chest H3can be reduced, and the occupant H is movable backward while the posture of the occupant H is maintained as much as possible.

In other words, the chest support member20and the head support member30are provided in the seat back S1and the headrest S3, respectively, such that the chest support member20moves backward first and the head support member30turns backward next when a backward movement load is applied to the occupant H. As illustrated inFIG.18, the chest support member20and the head support member30may be provided in the seat back and the headrest, respectively, such that the head support member300turns backward while the chest support member20moves backward, and thus both the chest support member20and the head support member30receive the backward movement load.

In addition, as illustrated inFIGS.17and18, in the head support member30of the conveyance seat200of the present embodiment, a portion facing the head H1of the occupant H is formed in a recessed shape to be recessed backward, and a portion facing the neck H2of the occupant H is formed in a protruding shape to protrude forward. Accordingly, the head H1and the neck H2of the occupant H are stably supported.

The embodiments of the present invention have been described above with reference to the drawings. In the above embodiments, the conveyance seats to be mounted in the vehicle have been described as a specific example; however, the conveyance seats are not limited to being mounted in the vehicle, and the conveyance seats of this application can also be provided as seats for trains, buses, or the like, and can also be used as seats for airplanes or ships.

REFERENCE SIGNS LIST