A structure of hydraulic damper comprising: - a cylinder having a bottom wall, a head wall and side walls that define a damping chamber having an inner lateral surface; - a piston having a first face and a second face opposite to each other suitable for sliding within said damping chamber along said inner lateral surface, in order to define a first and a second chamber separate from each other, said piston being suitable for carrying out a forward stroke between a first dead point at said bottom wall, towards a second dead point at said head wall, and a back stroke between said second dead point and said first dead point; - a shaft integral to said piston that extends outside beyond said head wall of said cylinder, in order to define an external connection end; - a damping fluid contained in said damping chamber; - a plurality of permanent holes suitable for permanently connecting said first chamber and said second chamber and allowing leakage of said damping fluid; - a plurality of apertures that extend from said first face to said second face of said piston; - wherein said plurality of apertures are associated to a plurality of plug elements pivotally connected by connection means on said first face or on said second face of said piston, and wherein said plurality of apertures are arranged in such a way that said plug elements move spontaneously from a closed configuration, in which said apertures are closed and allow the leakage of said damping fluid between said first chamber and said second chamber, only through said plurality of permanent holes, in order to damp the movement of said piston towards said second dead point, to an open configuration, in which they open said apertures and allow the free passage of said fluid between said first and second chambers (21,22), assisting the return movement towards said first dead point. - a cylinder having a bottom wall, a head wall and side walls that define a damping chamber having an inner lateral surface; - a piston having a first face and a second face opposite to each other suitable for sliding within said damping chamber along said inner lateral surface, in order to define a first and a second chamber separate from each other, said piston being suitable for carrying out a forward stroke between a first dead point at said bottom wall, towards a second dead point at said head wall, and a back stroke between said second dead point and said first dead point; - a shaft integral to said piston that extends outside beyond said head wall of said cylinder, in order to define an external connection end; - a damping fluid contained in said damping chamber; - a plurality of permanent holes suitable for permanently connecting said first chamber and said second chamber and allowing leakage of said damping fluid; - a plurality of apertures that extend from said first face to said second face of said piston; - wherein said plurality of apertures are associated to a plurality of plug elements pivotally connected by connection means on said first face or on said second face of said piston, and wherein said plurality of apertures are arranged in such a way that said plug elements move spontaneously from a closed configuration, in which said apertures are closed and allow the leakage of said damping fluid between said first chamber and said second chamber, only through said plurality of permanent holes, in order to damp the movement of said piston towards said second dead point, to an open configuration, in which they open said apertures and allow the free passage of said fluid between said first and second chambers (21,22), assisting the return movement towards said first dead point.