Screw and screw connection for components made of foamed plastic

A screw for a screw connection with a support component made of thermoplastic foam and comprising a tube with a predetermined degree of foaming of at least 2%, the screw comprising:

• a screw head;
• and
• a screw shaft comprising a blunt-edged thread for compacting the foam, the thread having flank angles (w) of 30°-90°;
• wherein:
• the ratio of an inner diameter of the tube to an outer diameter of the screw shaft is based on the degree of foaming of the tube, the ratio for a tube having a first degree of foaming being greater than the ratio for a tube having a second degree of foaming, the second degree of foaming being greater than the first degree of foaming.

A screw connection comprising:

• a support component made of thermoplastic foam, the support component comprising a tube with a predetermined degree of foaming of at least 2%;
• and
• a screw for connecting the support component to an additional component, the screw comprising a screw shaft having a blunt-edged thread for compacting the foam, the threads having flank angles (w) of 30°-90°;
• wherein the ratio of an inner diameter of the tube to an outer diameter of the screw shaft is based on the degree of foaming of the tube, the ratio for a tube having a first degree of foaming being greater than the ratio for a tube having a second degree of foaming, the second degree of foaming being greater than the first degree of foaming.

A method of connecting a support component to an additional component, the method including the following steps:

• forming, using one of a chemical or physical foaming process, the support component with a tube made of thermoplastic foam;
• providing a screw having multiple blunt-edged threads on a shaft of the screw, the threads having flank angles (w) of 30°-90°, wherein:
• an outer diameter of the shaft is larger at least in parts than an inner diameter of the tube;
• and
• a ratio of the inner diameter of the tube to the outer diameter of the shaft is based on the degree of foaming, the ratio for a tube having a first degree of foaming being greater than the ratio for a tube having a second degree of foaming, the second degree of foaming being greater than the first degree of foaming;
• placing an additional component onto the tube;
• and
• screwing in the screw in a non-thread-rolling manner through the additional component and into the tube, wherein the foam of the tube is compacted as the screw is driven in.