Rolling body screw device

A rolling body screw device comprising:

• a screw shaft having an outer surface in which a spiral rolling body rolling surface is formed;
• a nut member having an inner peripheral surface in which a spiral loaded rolling surface is formed so as to oppose to the rolling body rolling surface of the screw shaft and having a non-loaded rolling body passage;
• a pair of return pieces, one of the pair of return pieces being mounted to each end portion of the nut member, and including direction changing passages so as to form an endless track by connecting a loaded rolling body passage formed in association with the rolling body rolling surface and the loaded rolling surface and the non-loaded rolling body passage through the direction changing passages;
• and
• a number of rolling bodies rolling in the endless track, wherein
• each of the direction changing passages includes:
• a scoop-up portion scooping the rolling body rolling in the loaded rolling body passage as a loaded area of the endless track to the direction changing passage as a non-loaded area of the endless track;
• and
• a route path forming a circulation path of the rolling body scooped by the scoop-up portion, and
• each of the return pieces is composed, in combination, of a metal part formed of a metal material including the scoop-up portion, and a non-metal part formed of a non-metal material including the route path.