Aerodynamic device for motor-vehicle

1. An aerodynamic device for a motor-vehicle, comprising:

a panel structure located under a front part of the motor-vehicle and pivotally mounted around an axis transverse with respect to a longitudinal direction of the motor-vehicle, said panel structure being elastically biased towards a raised position and being adapted to be moved towards a lowered position when a motor-vehicle speed exceeds a predetermined threshold value, due to an airflow which invests the motor-vehicle, and

an upper wall which is fixed with respect to a motor-vehicle body, and placed above said panel structure so as to define a cavity together with said panel structure,

a bag structure arranged inside said cavity between said panel structure and said upper wall for receiving in its interior a portion of said airflow which invests the motor-vehicle during travel,

wherein above said predetermined threshold value of the motor-vehicle speed, said bag structure is inflated and pushes said panel structure towards its lowered position;

wherein said cavity vertically shrinks in a direction of a rear part of the motor-vehicle; and

wherein a front part of said upper wall and a front part of said panel structure are vertically spaced form each other, while a rear part of said upper wall and a rear part of said panel structure are adjacent to each other, in such a way to provide for said cavity vertically shrinking in the direction of the rear part of the motor-vehicle.

2. An aerodynamic device for a motor-vehicle, comprising:

a panel structure located under a front part of the motor-vehicle and pivotally mounted around an axis transverse with respect to a longitudinal direction of the motor-vehicle, said panel structure being elastically biased towards a raised position and being adapted to be moved towards a lowered position when a motor-vehicle speed exceeds a predetermined threshold value, due to an airflow which invests the motor-vehicle,

an upper wall which is fixed with respect to a motor-vehicle body, and placed above said panel structure so as to define a cavity together with said panel structure, and

a bag structure arranged inside said cavity between said panel structure and said upper wall for receiving in its interior a portion of said airflow which invests the motor-vehicle during travel,

wherein above said predetermined threshold value of the motor-vehicle speed, said bag structure is inflated and pushes said panel structure towards its lowered position,

wherein said device comprises at least one spring having a function of elastically biasing said panel structure towards said raised position, and

wherein said device further comprises an intermediate wall placed between said upper wall and said panel structure, in which said upper wall and said intermediate wall define a duct for directing said airflow inside said bag structure.

3. The device according to claim 2 , wherein said panel structure is pivotally mounted to a motor-vehicle bumper by at least one pivot pin, around a transverse axis with respect to the longitudinal direction of the motor-vehicle, and wherein said at least one spring is a coil spring wound around said pivot pin and has opposite ends operatively connected to the panel structure and to the bumper.

4. The device according to claim 2 , wherein said intermediate wall has its front edge rigidly fixed to the motor-vehicle bumper, and wherein said duct starts from an inlet opening located on a front surface of the motor-vehicle.

5. The device according to claim 4 , wherein said bag structure has a mouth connected to, and in communication with, a terminal end of said duct, in such a way that said duct conveys said airflow inside said bag structure.

6. The device according to claim 5 , wherein said bag structure comprises an outer bag element having an upper portion connected to said upper wall and having a lower portion connected to said panel structure.

7. The device according to claim 6 , wherein said bag structure further comprises an inner bag element, wherein said outer bag element and said inner bag element together define said mouth connected to, and in communication with, said terminal end of said duct for directing said airflow.

8. The device according to claim 4 , wherein said intermediate wall longitudinally extends inside said cavity and has a longitudinal extension lower than a longitudinal extension of said panel structure and of said upper wall.

9. An aerodynamic device for a motor-vehicle, comprising:

a panel structure located under a front part of the motor-vehicle and pivotally mounted around an axis transverse with respect to a longitudinal direction of the motor-vehicle, said panel structure being elastically biased towards a raised position and being adapted to be moved towards a lowered position when a motor-vehicle speed exceeds a predetermined threshold value, due to an airflow which invests the motor-vehicle,

an upper wall which is fixed with respect to a motor-vehicle body, and placed above said panel structure so as to define a cavity together with said panel structure, and

a bag structure arranged inside said cavity between said panel structure and said upper wall for receiving in its interior a portion of said airflow which invests the motor-vehicle during travel,

wherein above said predetermined threshold value of the motor-vehicle speed, said bag structure is inflated and pushes said panel structure towards its lowered position, and

wherein said panel structure has two opposite sides connected to a motor-vehicle structure, or connected to a front bumper secured to said motor-vehicle structure, by two flexible panels.

10. The device according to claim 4 , wherein said intermediate wall has at least one opening along its longitudinal extension, arranged for the drainage of any water which may have entered in the duct, in such a way as to avoid entrance of water inside said bag structure.