CROSS REFERENCE TO RELATED APPLICATIONS

This application is the U.S. National Stage entry of International Application Number PCT/JP2017/012585 filed under the Patent Cooperation Treaty having a filing date of Mar. 28, 2017, which claims priority to Japanese Patent Application No. 2016450359 having a filing date of Jul. 29, 2016, which are incorporated herein by reference.

TECHNICAL FIELD

The present invention relates to a vehicle seat configured to be mourned to a vehicle or the like.

BACKGROUND ART

In a rear seat of a vehicle having a seat cushion configured to seat two passengers, a buckle that can be coupled with a tongue plate of a seat belt is required to be provided in a rear central part of the seat cushion. In such a rear seat, it is known to provide a recess in a laterally extending frame portion positioned behind the seat cushion by curving a central part of the laterally extending frame portion in a forward direction, form a notch in a central part of the rear edge of the seat cushion, and provide an arm connecting a buckle to the floor of the vehicle to extend through the recess and the notch so that the buckle that is passed through the notch is located and exposed above the seat surface of the seat cushion. See Patent Document 1, for instance.

PRIOR ART DOCUMENT(S)

Patent Document(s)

Patent Document 1: JP3070393B

SUMMARY OF THE INVENTION

Task to be Accomplished by the Invention

However, the vehicle seat disclosed in Patent Document 1 is configured in such a manner that the buckle is always maintained above the seat surface of the seat cushion so the buckle prevents the seat back from being folded forward.

In view of such a problem of the prior art, a primary object of the present invention is to provide a vehicle seat having a seat back that can be folded forward, and prevent the buckle from interfering with the seat back when folding the seat back forward.

To achieve such an object, one embodiment of the present invention provides a vehicle seat, comprising: a seat back frame (F2) attached to a floor (FL) so as to be rotatable in a fore and aft direction within a prescribed range; a seat cushion frame (F1) rotatably attached to the seat back frame, and configured to move forward when the seat back frame is tilted forward; and a buckle support arm (44) having a base end attached to the floor so as to be rotatable in the fore and aft direction, and a free end fitted with a buckle (45) configured to be coupled with a tongue plate of a seat belt, the buckle support arm being rotatable between a use position where the buckle is positioned above the base end of the buckle support arm, and a stowed position where the buckle is positioned more forward than in the use position; wherein the seat cushion frame includes a pair of side frames located on either side and extending in the fore and aft direction, a front frame (12) extending between front parts of the side frames, and a rear frame (13) extending between rear parts of the side frames and provided with a curved portion (13A) protruding forward in a laterally middle part thereof, and wherein the buckle support arm is located behind the curved portion, the curved portion being dimensioned so as not to interfere with the buckle when the buckle support arm is in the stowed position.

Since the curved portion is dimensioned so as not to interfere with the buckle when the buckle support arm is in the stowed position, the buckle support arm can be positioned in the stowed position such that the buckle does not interfere with the seat back when the seat back is folded forward.

Preferably, in this embodiment, the curved portion is positioned in a rotational locus of the buckle support arm and the buckle when the seat cushion frame is positioned in a rearmost position in correspondence to a position of the seat back frame, and out of the rotational locus of the buckle support arm and the buckle when the seat cushion frame is positioned in a more forward position in correspondence to the position of the seat hack frame.

As the seat back frame rotates forward and the seat cushion frame moves forward, the buckle support arm moves to the stowed position. In particular, as the seat back tilts forward, the buckle support arm moves to the stowed position so that an interference between the buckle and the seat back can be avoided.

According to a preferred embodiment of the present invention, the vehicle seat further comprises a seat cushion pad (34) supported by the seat cushion frame, and provided with a recessed portion (34A) recessed forward from a part of a rear edge of the seat cushion frame corresponding to the curved portion, and the buckle support arm is positioned in the recessed portion in such a manner that the seat cushion pad is positioned in the rotational locus of the buckle support arm and the buckle when the seat cushion frame is positioned in the rearmost position in correspondence to the position of the seat back frame, and out of the rotational locus of the buckle support arm and the buckle when the seat cushion frame is positioned in a more forward position in correspondence to the position of the seat back frame.

Thereby, the size of the recessed portion of the seat cushion pad can be minimized so that the seat surface area of the seat cushion can be maximized.

Preferably, in any of the foregoing embodiments, an upper end of the buckle is lower than an upper surface of the seat cushion pad in the stowed position.

Thereby, when the seat back is folded forward, the buckle in the stowed position is prevented from interfering with the seat back.

Preferably, in any of the foregoing embodiments, the vehicle seat further comprises a biasing device (47) for urging the buckle support arm toward the use position.

Thereby, when the vehicle seat is in the use position, the buckle support arm is urged toward the use position by the biasing device.

Preferably, in any of the foregoing embodiments, the vehicle seat further comprises a reinforcing member (16) extending in the fore and aft direction between the curved portion and the front frame.

Thereby, the stiffness of the seat cushion frame is maintained even when the rear frame is provided with the curved portion.

Preferably, in any of the foregoing embodiments, the vehicle seat further comprises an intermediate frame (14) extending laterally between the side frames intermediately between the front frame and the rear frame, and a reinforcing member (16) extending in the fore and aft direction between the curved portion and the intermediate frame.

According to this arrangement, the intermediate frame effectively increases the stiffness of the seat cushion frame. Even though the rear frame is provided with the curved portion, the stiffness of the seat cushion frame is maintained by the reinforcing member.

Preferably, in any of the foregoing embodiments, the rear frame includes a left portion (13B) and a right portion (13C) extending laterally on either side of the curved portion, and the seat cushion frame defines a pair of seating parts, the left portion forming a rear part of one of the seating parts, the right portion forming a rear part of the other of the seating parts, and the curved portion is positioned at a boundary between the two seating parts.

Since the curved portion is positioned away from the buttocks of the occupants of the two seating parts of the seat configured to seat two occupants, the occupants are prevented from experiencing any discomfort which could be otherwise caused by the curved portion.

Preferably, in any of the foregoing embodiments, the curved portion, the left portion, and the right portion are formed by a continuous pipe member.

Thereby, the rear frame has a simple structure.

Preferably, in any of the foregoing embodiments, the left portion and the right portion are vertically offset from each other.

Thereby, the thickness of the seat cushion pad for a part of the seat cushion located in a part of the rear frame which is downwardly offset can be increased.

Preferably, in any of the foregoing embodiments, the seat cushion frame forms two seating parts in a rear seating arrangement including a left seating part (31), a middle seating part (32), and a right seating part (3) that are arranged laterally, the two seating parts being formed by one of the left and right seating parts, and the middle seating part, and one of the left portion and the right portion corresponding to the left seating part or the right seating part is offset downward relative to the other of the left portion and the right portion corresponding to the middle seating part.

Thereby, the thickness of the seat cushion pad in the left seating part or the right seating part, which is used more frequently than the middle seating part can be given with an increased thickness.

Preferably, in any of the foregoing embodiments, the vehicle seat further comprises a rear frame reinforcing member (15) connected to the left portion and the right portion, and curved and/or bent downward in a part thereof corresponding to the curved portion.

Thereby, the rear frame can be reinforced without interfering with the buckle support arm.

Preferably, in any of the foregoing embodiments, the curved portion has a V shaped configuration projecting forward in plan view.

Thereby the structure of the rear frame is simplified and manufacturing thereof is facilitated.

Effect of the Invention

According to the above structure, in the vehicle seat having the seat back that can be tilted forward, the buckle can be prevented from interfering with the seat back when the seat back is tilted forward.

