Wheel rim structure for motor-vehicles

A wheel rim for motor-vehicles comprising:

• a peripheral structure that extends circumferentially around a predefined first axis, said peripheral structure being arranged to receive a tire;
• and
• a central structure, integrated with said peripheral structure and provided with means for coupling, along said first axis, with a hub of the motor-vehicle,
• wherein said peripheral structure comprises an axially inner portion, an axially outer portion and a central portion, interposed between said axially inner portion and said axially outer portion, wherein said central portion comprises a circumferential well, where the radius of the wheel rim is minimum, wherein said wheel rim is symmetrical with respect to a second axis perpendicular to said first axis and passing through a centre-line of said central portion, and wherein each of said axially inner portion and said axially outer portion comprises in sequence:
• a respective peripheral flange;
• a respective connecting wall, which joins the respective peripheral flange and extends axially towards said central portion, wherein the respective connecting wall is substantially frustoconical and has a first axial end with greater radius, the first axial end joined to the respective peripheral flange, and a second axial end with lesser radius, the second axial end disposed opposite the first axial end and facing said central portion, and wherein the respective connecting wall, together with the respective peripheral flange, forms a seat for receiving the bead of said tire;
• a connecting part, which is interposed between the respective connecting wall and said central portion,
• wherein the connecting part of at least one of said axially inner portion and said axially outer portion comprises a first curved region which connects with said central portion,
• the connecting part which comprises said first curved region, further comprises a second curved region which is interposed between said first curved region and the second axial end with lesser radius of the respective connecting wall, said first curved region comprising:
• a first concave surface, a second concave surface, and a third concave surface which are axially spaced, interspersed with two respective convex surfaces, said concave surfaces and said two convex surfaces extending circumferentially when seen from the side of the wheel rim on which said tire is fitted;
• said second curved region having a convex profile when seen from the side of the wheel rim on which said tire is fitted, said second curved region comprising:
• a first curved surface, which is joined to the second axial end with lesser radius of the respective connecting wall, the first curved surface having a first radius of curvature;
• and
• a second curved surface, which is interposed between said first curved surface and said first concave surface of the first curved region such that the second curved surface separates the first curved surface from the first concave surface, the second curved surface having a second radius of curvature different from said first radius of curvature such that the second curved region includes different curvatures between the first curved surface and the second curved surface.