Hollow metallic shaft for e.g. printer rollers, has metallic hollow shaft with more than three segments with concave portion between two adjacent section and sum of length of arc portions follows preset equation

摘要

A hollow cylindrical metallic shaft fits into hole of component such as bearing. Hollow shaft has three or more peripheral segments (m1-m3) with portion between adjacent segments joined by concave portions (n1-n3). Radius of shaft before fitment is Rs. Rt is radius of shaft after fitment to hole portions. The length of arc segments are Lm1,Lm2... The shaft satisfies condition: Lm1+Lm2.. is less than 2 pi Rt.