Assembly unit

An assembly unit, comprising:

• an assembly part, having an assembly side, an outer side opposite said assembly side, and a through opening extending between said outer side and said assembly side;
• a screw, having a head projecting radially above said through opening on said outer side and a shank reaching through said through opening, said shank having a threaded portion and a non-threaded portion disposed between said threaded portion and said head;
• a holder fixing said screw captively in said through opening, said holder being held with axial movability in said through opening and with axial movability on said non-threaded shank portion of said screw;
• said holder having a disk-shaped flange with a flange opening accommodating said non-threaded portion of said shank, an inner rim bounding said flange opening and an outer rim delimiting said flange;
• said inner rim forming at least one first retaining element, which juts into an undercut space extending between said head of said screw and a shank projection at an axial spacing distance from said head;
• a plurality of spring arms molded onto said outer rim, said spring arms being spaced apart in a peripheral direction of said flange and extending away toward a shank end distal from said head, said spring arms having free ends bearing a radially outwardly protruding second retaining element, which, in a first axial position, in which said holder projects with a maximum projecting length from said outer side of the assembly part, bears against a stop element projecting radially inward from a wall of said through opening, on a side of said stop element facing away from said head of said screw.