Patent ID: 7395743

Claim:
A lathe spindle unit comprising: a rotatable spindle having a cam follower, and a holding section for holding a work piece; a drive source for rotatively driving said spindle; a driven rotation shaft that has a cam and that is rotatively driven by said drive source, said driven rotation shaft rotatively driving said spindle using said cam and said cam follower, and a supporting section for rotatably supporting said spindle; wherein a first V-shaped groove is formed directly in said spindle along the rotation direction of said spindle, and said supporting section has a second V-shaped groove that is in opposition to said first V-shaped groove; and wherein a cross roller bearing is made by interposing, between said spindle and said supporting section, a plurality of rolling elements that roll while being in contact with said first V-shaped groove and said second V-shaped groove, and making the axis of rolling of adjacent rolling elements be perpendicular to one another.