Patent ID: 8356860

Claim:
A seat device for a vehicle, comprising: a seat for a passenger, the seat including a seatback to support a passenger's back portion; a reinforcing structure body provided inside seatback of said seat, extending along an outer periphery of the seatback, said reinforcing structure body including an upper portion, a lower portion, and a side portion extending between said upper portion and said lower portion; a headrest provided at the upper portion of said reinforcing structure body to support a passenger's head portion; a connection support portion provided beside said reinforcing structure body at a position in a vertical direction between the upper portion and the lower portion to connect said reinforcing structure body to a vehicle-body member so as to support the reinforcing structure body at the vehicle-body member, the connection support portion including a pivotally-supporting portion to pivotally support the reinforcing structure body at the vehicle-body member around a pivotal axis thereof, the pivotal axis of the pivotally-supporting portion being configured such that a position of the pivotal axis does not move rearwardly relative to the vehicle-body member; and a move-allowance portion allowing a lower portion of said reinforcing structure body to move rearwardly relative to the vehicle-body member, whereby when the seatback is pressed rearwardly by the passenger's back portion in a vehicle rear collision, the reinforcing structure body of the seat is rotatable around the pivotal axis of the pivotally-supporting portion of the connection support portion such that the upper portion of the reinforcing structure body with the headrest moves forwardly, the lower portion of the reinforcing structure body moves rearwardly and the pivotal axis of the pivotally-supporting portion does not move rearwardly relative to the vehicle-body member, so that said headrest moves forwardly or upwardly.