Door made of plastic material for motor vehicles

A motor vehicle door formed of plastic material whose parts are substantially manufactured by injection molding, said door consisting of a center single-piece support construction for transmitting forces to the frame of the body of the motor vehicle, an outer door shell and an inner door shell secured on said support construction, the support construction being formed of an outer profiled frame extending around the periphery of said door and being provided with stiffening elements and a reinforcement arranged beneath the window opening, the improvement comprising:

• said profiled frame having a steplessly changing profile cross section along the door periphery, the stiffening elements of said profiled frame being formed by injection molded stiffening ribs, and the reinforcement arranged beneath the window opening being injection molded in the profiled frame and consisting of horizontally extending load profiles and vertically extending ribs forming a lattice construction extending throughout the door beneath the window opening.