Ball screw

A ball screw, comprising:

• a screw including at least two track grooves;
• a nut slidingly disposed on the screw and including:
• a nut body having two assembly openings, wherein the inside of the nut body includes at least two inner ball grooves corresponding to the track grooves, respectively, the inner ball grooves and the track grooves constitute two inner ball channels, the nut body includes two reflowing channels corresponding to the inner ball channels, and the reflowing channels and the inner ball channels constitute a part of two ball circulation channels of the ball screw;
• and
• at least one end assembly, including:
• an end circulation member disposed to the nut body and including at least two circulation portions which are disposed in the assembly openings, respectively;
• a dust-proof member disposed on the side of the end circulation member away from the nut body;
• and
• a fastening member disposed on the side of the dust-proof member away from the end circulation member, wherein one side of the fastening member includes a plurality of projections and the other side of the fastening member includes a plurality of indentations corresponding to the projections;
• and
• a plurality of balls disposed within the ball circulation channels.