Pulley and rolling bearing with resin pulley

摘要

The object is to suppress beating sounds produced while a pulley is rotating in a simple manner at a low cost. A mold 9 for forming the pulley has gate holes 10 through which resin is injected into the mold 9. Not all of the gate holes 10 have the same diameter, and also, the gate holes 10 are arranged so as to be rotationally asymmetric about the rotation axis of the pulley. Further, a plurality of ribs 7 reinforcing a disk portion 6 disposed between radially inner and outer cylindrical portions 5 and 3 of the pulley are designed such that not all of the ribs 7 have the same thickness. With these arrangements, portions of the resin injected through the respective gate holes 10 reach the portion in the cavity 8 of the mold corresponding to the radially outer cylindrical portion 5 at different times, thus making the outer diameter of the radially outer cylindrical portion 5 rotationally asymmetric. This reduces interference of a plurality of sounds produced from the pulley, thereby suppressing beating sounds.