Seat for a vehicle with filling of the space between backrest and seat cushion

A seat for a vehicle comprising:

• a base structure, which is rigid, is configured to be fixed to a floorboard of the vehicle and is divided into a cushion and a backrest spaced apart from the cushion, thus defining a space between the backrest and the cushion;
• an upholstery, which is elastically deformable, at least partially covers the base structure, constitutes an outermost part of the seat that is configured to come into contact with a body of a passenger of the seat and has at least one component fixed to the base structure;
• a filling system provided with a filling body, which can assume a passive position, in which the filling body is external to the space between the backrest and the cushion, and an active position, in which the filling body at least partially occupies and fills the space between the backrest and the cushion;
• wherein the filling system comprises an actuator device configured to alternately move the filling body to the passive position or to the active position.