| 20100148455 | Tool holder - A tool holder includes: a collet chuck main body having a tapered hole formed in its tip end portion so as to be tapered toward an axial rear end; a tapered collet having a tool insertion hole that extends in an axial direction, a main tapered surface that fits in the tapered hole, and a tip end tapered surface positioned on an axial tip end side of the main tapered surface, and tapered toward an axial tip end; a cylindrical lock nut having internal threads that are screwed on external threads formed on an outer periphery of the tip end portion of the collet chuck main body, for reducing a diameter of the tool insertion hole by pressing the tapered collet into the tapered hole; a tip end tapered member having a tapered abutting surface that fits on the tip end tapered surface, the tip end tapered member being pressed toward the axial rear end by the lock nut; and a plain bearing positioned in a plane perpendicular to a direction in which the tip end tapered member is pressed by the lock nut, the plain bearing being inserted between the lock nut and the tip end tapered member. | 06-17-2010 |
