Ball screw device having bearing spacer

A ball screw device comprising:

• a ball nut including a bore formed therein, and including an inner thread formed therein and defined by a plurality of helical groove portions for forming an endless ball rolling passage in said ball nut, and including an endless spacer moving passage in said ball nut and communicating with said endless ball rolling passage of said ball nut,
• a plurality of bearing members engaged in said endless ball rolling passage of said ball nut, and
• a plurality of spherical bearing spacers engaged in said endless spacer moving passage of said ball nut and engaged between said bearing members for spacing said bearing members away from each other and for preventing said bearing members from striking onto each other.